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Abbre­vi­ation of two-dimen­sion­al. It refers to things that take up space or hap­pen in two dimen­sions (plane).


An advanced tech­nique for semi­con­duct­or pack­aging where dice are placed on an inter­poser that uses through-sil­ic­on vias and redis­tri­bu­tion lay­ers for inter­con­nect­ing the dice. Des­pite being closely pack­aged, dice in this con­fig­ur­a­tion com­mu­nic­ate through off-chip sig­nal­ing, akin to their oper­a­tion when placed in sep­ar­ate pack­ages on a stand­ard cir­cuit board.


Abbre­vi­ation of three-dimen­sion­al. It refers to things that take up space or hap­pen in three dimensions.


The pro­cess of stack­ing dif­fer­ent integ­rated cir­cuit dice with­in a single pack­age, using inter­posers for elec­tric­al con­nec­tions. Unlike 3D integ­ra­tion, this meth­od does not involve alter­ing the sil­ic­on itself but focuses on pack­age-level stack­ing. It provides ver­sat­il­ity in com­bin­ing vari­ous tech­no­lo­gies and mater­i­als and is less com­plex than 3D integ­ra­tion, offer­ing a prac­tic­al solu­tion for integ­rat­ing diverse com­pon­ents in a single package.


A 3D integ­ra­tion tech­nique that uses 3D integ­ra­tion to cre­ate mul­tiple stacks of dice stacked on top of each and 2.5D integ­ra­tion to con­nect the stacks using a sil­ic­on inter­poser. In jest, this is some­times called the 5.5D IC because it com­bines 2.5D and 3D.


Ver­tic­ally stack­ing and inter­con­nect­ing sil­ic­on wafers or dice to func­tion as a single device. This tech­nique, which uses through-sil­ic­on vias for dir­ect lay­er-to-lay­er com­mu­nic­a­tion, aims to enhance device per­form­ance and func­tion­al­ity in a com­pact space. It is char­ac­ter­ized by its ver­tic­al integ­ra­tion approach, improved sig­nal trans­mis­sion speed, reduced power con­sump­tion, and the need for pre­cise align­ment and bond­ing meth­ods, mak­ing it a com­plex yet effi­cient man­u­fac­tur­ing process.


See ampere.

absolute permittivity

A meas­ure of a material’s abil­ity to polar­ize in response to an applied elec­tric field and thereby store elec­tric­al energy. It is often denoted ε. It quan­ti­fies the elec­tric polar­iz­ab­il­ity of a dielec­tric. The high­er the abso­lute per­mit­tiv­ity, the more a mater­i­al can polar­ize and the more energy it can store when sub­jec­ted to an elec­tric field.


See altern­at­ing cur­rent.

active component

A com­pon­ent that requires an extern­al power source to func­tion or can provide power to a cir­cuit. These com­pon­ents are involved in func­tions like amp­li­fic­a­tion, rec­ti­fic­a­tion, sig­nal pro­cessing, and power gen­er­a­tion. Examples include tran­sist­ors, diodes, integ­rated cir­cuits, and batteries.

advanced packaging

Refers to innov­at­ive and soph­ist­ic­ated tech­niques in semi­con­duct­or encap­su­la­tion that aim to improve per­form­ance, reduce size, and integ­rate addi­tion­al fea­tures. This sub­set of semi­con­duct­or pack­aging goes bey­ond tra­di­tion­al meth­ods to address chal­lenges in high-per­form­ance com­put­ing, mini­atur­iz­a­tion, and com­plex cir­cuit integ­ra­tion. 3D pack­aging and Sys­tem in Pack­age (SiP) are key tech­no­lo­gies in advanced packaging.


See anion exchange mem­brane.

AEM electrolysis

See anion exchange mem­brane elec­tro­lys­is.

AEM electrolyzer

See anion exchange mem­brane elec­tro­lyz­er.

AEM water electrolysis

See anion exchange mem­brane elec­tro­lys­is.

AEM water electrolyzer

See anion exchange mem­brane water elec­tro­lyz­er.


See atom­ic lay­er depos­ition.


See alkaline.

ALK electrolysis

See alkaline elec­tro­lys­is.

ALK electrolyzer

See alkaline elec­tro­lyz­er.

ALK water electrolysis

See alkaline elec­tro­lys­is.

ALK water electrolyzer

See alkaline water elec­tro­lyz­er.


Adject­ive describ­ing a sub­stance that is water sol­uble and has a pH great­er than 7.0 or a solu­tion of such a substance.

alkaline electrolysis

Elec­tro­lys­is char­ac­ter­ized by hav­ing elec­trodes oper­at­ing in a liquid alkaline elec­tro­lyte solu­tion, typ­ic­ally potassi­um hydrox­ide (KOH) or sodi­um hydrox­ide (NaOH).

alkaline electrolyzer

Elec­tro­lyz­er for alkaline elec­tro­lys­is. Alkaline water elec­tro­lys­is is an import­ant application.

alkaline water electrolysis (AKLWE)

Elec­tro­lys­is by means of an alkaline elec­tro­lyz­er for the pur­pose of split­ting water into hydro­gen and oxy­gen. Its major advant­age is that a high-cost noble met­al cata­lyst is not required; a low-cost elec­tro­lyte solu­tion is used instead. How­ever, alkaline water elec­tro­lys­is has sev­er­al draw­backs com­pared to pro­ton exchange mem­brane elec­tro­lys­is. Most not­able are lower energy effi­ciency, sens­it­iv­ity to changes in power input, and less pur­ity of the pro­duced hydrogen.

alkaline water electrolyzer

Alkaline elec­tro­lyz­er built for the pur­pose of water elec­tro­lys­is. See also alkaline water elec­tro­lys­is.

alternating current (AC)

A type of elec­tric­al cur­rent in which the dir­ec­tion of the flow of elec­trons switches back and forth at reg­u­lar inter­vals or cycles.

ampere (A)

The SI unit of elec­tric cur­rent rep­res­ents a flow of one cou­lomb of charge per second.


A neg­at­ively charged ion is formed when an atom or molecule has excess neg­at­ive charge in the form of elec­trons. Dur­ing elec­tro­lys­is, anions have a tend­ency to accu­mu­late at the anode (pos­it­ive elec­trode) in an elec­tro­lyte solution.

anion exchange membrane

A mem­brane that select­ively allows the pas­sage of anions while mostly block­ing cations or neut­ral molecules com­monly used in vari­ous elec­tro­chem­ic­al pro­cesses like elec­tro­lys­is and fuel cells.

anion exchange membrane electrolysis

Elec­tro­lys­is char­ac­ter­ized by hav­ing elec­trodes on each side of an anion exchange mem­brane.

anion exchange membrane electrolyzer

Elec­tro­lyz­er for anion exchange mem­brane elec­tro­lys­is. Anion exchange mem­brane water elec­tro­lys­is is an import­ant application.

anion exchange membrane water electrolysis (AEMWE)

Elec­tro­lys­is by means of an anion exchange mem­brane elec­tro­lyz­er for the pur­pose of split­ting water into hydro­gen and oxy­gen. Its major advant­age is that a high-cost noble met­al cata­lyst is not required; a low-cost trans­ition met­al cata­lyst can be used instead. How­ever, it is still in the early research and devel­op­ment stage, while alkaline water elec­tro­lys­is is in the mature stage, and pro­ton exchange mem­brane elec­tro­lys­is is in the com­mer­cial stage.

anion exchange membrane water electrolyzer

Anion exchange mem­brane elec­tro­lyz­er built for the pur­pose of water elec­tro­lys­is. See also anion exchange mem­brane water elec­tro­lys­is.


An elec­trode of a polar­ized elec­tric­al device through which con­ven­tion­al cur­rent enters the device. Elec­trons flow from the device to the anode. In elec­tro­chem­ic­al cells, oxid­a­tion occurs at the anode. In pro­ton exchange mem­brane elec­tro­lyz­ers, iridi­um is used in the anode.

anti-corrosion material

Mater­i­al that res­ists cor­ro­sion and is used to pro­tect oth­er mater­i­als, e.g., plat­in­um, is used in electrolyzers.

atomic layer deposition (ALD)

A thin film depos­ition tech­nique that depos­its mater­i­als lay­er by lay­er at the atom­ic level. Dur­ing atom­ic lay­er depos­ition, pre­curs­or gases are pulsed into a reac­tion cham­ber sequen­tially, allow­ing for pre­cise film thick­ness and com­pos­i­tion con­trol. This meth­od ensures high-qual­ity and uni­form films even on com­plex surfaces.

available surface area

In the con­text of an elec­tro­chem­ic­al cell, such as those used in pro­ton exchange mem­brane (PEM) elec­tro­lyz­ers, avail­able sur­face area refers to the area of the elec­trode sur­faces that act­ively par­ti­cip­ate in elec­tro­chem­ic­al reactions.

balance of plant (BoP)

All the sup­port­ing com­pon­ents and sys­tems required to oper­ate an elec­tro­lyz­er effect­ively, exclud­ing the elec­tro­lyz­er stack itself.

ball grid array (BGA)

A chip pack­aging scheme in which the bot­tom of the pack­age is covered in a grid-like pat­tern of solder balls. These solder balls provide the elec­tric­al con­nec­tions between the chip and the sub­strate it is soldered onto, such as a prin­ted cir­cuit board.


The energy dif­fer­ence between the valence band’s top and the con­duc­tion band’s bot­tom. It is a cru­cial para­met­er that determ­ines the elec­tric­al con­duct­iv­ity of a semi­con­duct­or. A lar­ger bandgap means more energy is required for an elec­tron to move from the valence band to the con­duc­tion band. Semi­con­duct­ors with a small bandgap are more eas­ily excited and can con­duct elec­tri­city more read­ily. In con­trast, those with a large bandgap are less conductive.

bipolar plate

A slim, flat com­pon­ent, often made of graph­ite or met­al, fea­tur­ing intric­ate chan­nels on its sur­face. It’s used with­in the elec­tro­lyz­er stack, where it serves a dual pur­pose: con­nect­ing the anode of one cell to the cath­ode of anoth­er while also man­aging water and gas flow. Its thin­ness and chan­nel design are cru­cial for effi­ciency, mak­ing it a key ele­ment in the stack’s over­all performance.


See ball grid array.

black hydrogen

Hydro­gen gen­er­ated from lower-grade coal, like lig­nite, through a pro­cess known as coal gas­i­fic­a­tion. Black hydro­gen pro­duc­tion is highly pol­lut­ing, releas­ing a con­sid­er­able amount of car­bon diox­ide and oth­er harm­ful emis­sions due to the com­bus­tion of coal. See also green hydro­gen, blue hydro­gen, grey hydro­gen, and brown hydro­gen.

blue hydrogen

Hydro­gen gen­er­ated from nat­ur­al gas through pro­cesses such as steam meth­ane reform­ing or auto­therm­al reform­ing, where the car­bon emis­sions are cap­tured and stored, redu­cing its envir­on­ment­al impact. See also green hydro­gen, grey hydro­gen, brown hydro­gen, and black hydro­gen.

brown hydrogen

Hydro­gen gen­er­ated from high­er-grade coal through a pro­cess known as coal gas­i­fic­a­tion. Brown hydrogen’s pro­duc­tion is highly pol­lut­ing, releas­ing a con­sid­er­able amount of car­bon diox­ide and oth­er harm­ful emis­sions due to the com­bus­tion of coal. See also green hydro­gen, blue hydro­gen, grey hydro­gen, and black hydro­gen.


See solder balls.


See com­pound annu­al growth rate.


See capa­cit­or.


The abil­ity of a capa­cit­or to store an elec­tric charge is meas­ured in farads (F). It rep­res­ents the charge a capa­cit­or can hold for a giv­en voltage across its terminals.


An elec­tron­ic com­pon­ent that stores and releases elec­tric­al energy con­sists of two con­duct­ing plates sep­ar­ated by an insu­lat­ing mater­i­al, which is dielec­tric. Some­times abbre­vi­ated cap.

carbon dioxide (CO2)

A col­or­less, odor­less gas that arises from vari­ous nat­ur­al pro­cesses, such as res­pir­a­tion and vol­can­ic erup­tions, and human activ­it­ies, primar­ily burn­ing fossil fuels. Elev­ated car­bon diox­ide levels in the atmo­sphere are a chief con­trib­ut­or to the green­house effect, glob­al warm­ing, and cli­mate change. Lim­it­a­tion of green­house gas emis­sions is a primary goal for those advoc­at­ing for fossil-free energy sources.

carbon nano-growth tool

Equip­ment designed to facil­it­ate the growth or syn­thes­is of car­bon-based nano­struc­tures, such as nan­ofibers, nan­otubes, or graphene.

carbon nanofiber (CNF)

A type of nan­ofiber com­posed of car­bon atoms. These fibers exhib­it unique mech­an­ic­al, elec­tric­al, and thermal prop­er­ties, mak­ing them suit­able for vari­ous applic­a­tions. Grow­ing car­bon nan­ofiber is Smoltek’s core competence.

carbon nanotechnology

The study, manip­u­la­tion, and applic­a­tion of car­bon-based nano­scale struc­tures, includ­ing car­bon nan­ofibers, nan­otubes, and graphene.


Refers to pro­cesses, activ­it­ies, or energy sources that do not release car­bon diox­ide (CO2) into the atmo­sphere. For example, renew­able energy sources like sol­ar and wind power are con­sidered car­bon-free because they gen­er­ate elec­tri­city without emit­ting CO2. See also car­bon-neut­ral and fossil-free.


Means that any CO2 released into the atmo­sphere from a cer­tain activ­ity is bal­anced out by an equi­val­ent amount of CO2 being removed. This can be achieved through vari­ous means, such as car­bon off­set­ting, where CO2 emis­sions are com­pensated for by fund­ing renew­able energy pro­jects, tree plant­ing, or oth­er activ­it­ies that absorb CO2. See also car­bon-free and fossil-free.


A sub­stance that facil­it­ates a chem­ic­al reac­tion without under­go­ing any per­man­ent chem­ic­al change itself.

catalyst support

A mater­i­al on which a cata­lyst is dis­persed or attached increas­ing the avail­able sur­face area and sta­bil­ity of the catalyst.


An elec­trode of a polar­ized elec­tric­al device through which con­ven­tion­al cur­rent leaves the device. Elec­trons flow to the device from the cath­ode. In elec­tro­chem­ic­al cells, reduc­tion occurs at the cathode.


A pos­it­ively charged ion is formed when an atom or molecule has an excess pos­it­ive charge lack­ing one or sev­er­al elec­trons. In an elec­tro­lyte solu­tion, cations move toward the cath­ode dur­ing electrolysis.


See elec­tro­chem­ic­al cell.

cell area

The sur­face area of the elec­trodes where the elec­tro­chem­ic­al reac­tions occur in an elec­tro­chem­ic­al cell.

chemical vapor deposition (CVD)

A meth­od used to pro­duce thin films or coat­ings on a sub­strate by chem­ic­ally react­ing gaseous pre­curs­ors at or near the sub­strate sur­face. The sub­strate is exposed to one or more vapor­ized pre­curs­or mater­i­als dur­ing this pro­cess. As these pre­curs­ors come into con­tact with the sub­strate, they react or decom­pose, form­ing a sol­id depos­it. Chem­ic­al vapor depos­ition is the main pro­cess when grow­ing car­bon nanofibers.


See integ­rated cir­cuit.

chip-on-board (COB)

A chip pack­aging scheme where the semi­con­duct­or die is moun­ted dir­ectly onto a cir­cuit board and then covered with a pro­tect­ive epoxy or sim­il­ar material.

circuit board

A flat board made from non-con­duct­ive mater­i­al with con­duct­ive traces etched or prin­ted on it, on which elec­tron­ic com­pon­ents are moun­ted and elec­tric­ally connected.

climate change

Refers to sig­ni­fic­ant changes in glob­al tem­per­at­ures and weath­er pat­terns over exten­ded peri­ods. While cli­mate change is a nat­ur­al phe­nomen­on, cur­rent pat­terns are heav­ily influ­enced and accel­er­ated by human activ­it­ies, espe­cially the burn­ing of fossil fuels. This has led to vari­ous envir­on­ment­al and soci­et­al chal­lenges, includ­ing more fre­quent and severe weath­er events, altered eco­sys­tems, and rising sea levels. Vari­ous inter­na­tion­al frame­works, includ­ing the Sus­tain­able Devel­op­ment Goals, the UN Frame­work Con­ven­tion on Cli­mate Change, and the Par­is Agree­ment, out­line neces­sary meas­ures to address cli­mate change. These include redu­cing emis­sions, adapt­ing to cli­mate-related impacts, and secur­ing the fund­ing needed for these adapt­a­tions. Encour­aging the use of fossil-free energy sources and green hydro­gen is essen­tial in the effort to halt cli­mate change.

climate crisis

A term emphas­iz­ing the urgent and severe nature of cli­mate change. It high­lights the imme­di­ate need for action to address the escal­at­ing chal­lenges of rising tem­per­at­ures, sea-level rise, extreme weath­er events, and oth­er mani­fest­a­tions of dis­rup­ted cli­mate pat­terns. Due to the crisis, many new tech­no­lo­gies are being developed and are expec­ted to reach large mar­kets in the future.


Abbre­vi­ation of com­ple­ment­ary met­al-oxide-semi­con­duct­or, which comes from the use of com­ple­ment­ary and sym­met­ric­al pairs of p‑type and n‑type MOS­FETs where the MOSFET hav­ing a met­al gate elec­trode placed on top of an oxide insu­lat­or, which in turn is on top of a semi­con­duct­or mater­i­al. Since one tran­sist­or of the MOSFET pair is always off, the series com­bin­a­tion draws sig­ni­fic­ant power only moment­ar­ily dur­ing switch­ing between on and off states. Con­sequently, CMOS devices do not pro­duce as much waste heat as oth­er forms of logic. CMOS is also used in a gen­er­al sense to refer to both the type of cir­cuitry that uses CMOS tech­no­logy and the pro­cess of man­u­fac­tur­ing with CMOS technology.


See car­bon nan­ofiber.


Smoltek’s trade­mark car­bon nan­ofiber enhanced met­al-insu­lat­or-met­al capa­cit­ors.


See car­bon diox­ide.


See chip-on-board.

complementary metal-oxide-semiconductor (CMOS)



A spe­cif­ic device or ele­ment with­in a tech­nic­al sys­tem, such as an elec­tric­al or elec­tron­ic cir­cuit, serves a dis­tinct pur­pose, such as modi­fy­ing, amp­li­fy­ing, or dir­ect­ing elec­tric­al cur­rent or sig­nals. Elec­tron­ic com­pon­ents can be as simple as res­ist­ors or capa­cit­ors or as com­plex as integ­rated cir­cuits and are the fun­da­ment­al build­ing blocks for design­ing and assem­bling elec­tric­al cir­cuits and systems.

Compound annual growth rate (CAGR)

A meas­ure that shows the con­sist­ent growth rate of, for instance, a mar­ket or an invest­ment over mul­tiple years. It helps under­stand how much an invest­ment has grown on aver­age each year over a spe­cif­ic period.


See elec­tric­al con­duct­iv­ity.

conduction band

A band of energy levels above the valence band where elec­trons can move freely through the mater­i­al, thus con­trib­ut­ing to elec­tric­al con­duct­iv­ity. When elec­trons in a semi­con­duct­or gain enough energy (for example, from heat or light), they can be excited from the valence band into the con­duc­tion band, allow­ing the mater­i­al to con­duct elec­tric current.


A device for con­nect­ing two dif­fer­ent parts to trans­mit elec­tric sig­nals or power.


The nat­ur­al pro­cess by which mater­i­als deteri­or­ate due to reac­tions with their envir­on­ment, often res­ult­ing in the form­a­tion of oxides or salts of the ori­gin­al mater­i­al. Anti-cor­ro­sion mater­i­als can be used to pro­tect materials.

Cu-Cu connection

A type of bond made dir­ectly between two cop­per sur­faces, used in advanced pack­aging semi­con­duct­ors.


Refers to the flow of elec­tric charge car­ri­ers, such as elec­trons or ions, through a con­duct­or or cir­cuit. It rep­res­ents the rate at which elec­tric charges move past a spe­cified point in the cir­cuit, and it’s meas­ured in units of amperes (A).

current density

The amount of elec­tric cur­rent flow­ing through a spe­cif­ic cross-sec­tion­al area of a material.

customer sample

See engin­eer­ing sample.


See chem­ic­al vapor depos­ition.


See die-to-wafer.

direct current (DC)

A type of elec­tric­al cur­rent where the flow of elec­trons is con­sist­ent and moves in one direction.


See dir­ect cur­rent.

decoupling capacitor

A capa­cit­or is used in cir­cuits to sep­ar­ate AC and DC sig­nals, pre­vent­ing noise dis­turb­ances from affect­ing oth­er parts of the circuit.


The pro­cess of depos­it­ing a mater­i­al, often in the form of a thin film or coat­ing, onto a sur­face. Depos­ition tech­niques are widely used in vari­ous indus­tries, includ­ing elec­tron­ics and man­u­fac­tur­ing, to cre­ate lay­ers with spe­cif­ic properties.


Incor­por­at­ing a spe­cif­ic com­pon­ent or tech­no­logy into a product’s ini­tial design phase.


A situ­ation where a com­pon­ent or tech­no­logy sup­pli­er gets its product chosen for use in a new product developed by a manufacturer.


Plur­al form of die.


A small block of semi­con­duct­or mater­i­al has been pro­cessed to cre­ate an elec­tric­al cir­cuit in which a large num­ber of mini­atur­ized tran­sist­ors and oth­er elec­tron­ic com­pon­ents are insep­ar­ably assembled and elec­tric­ally interconnected.

die-to-wafer (D2W)

A man­u­fac­tur­ing concept in which indi­vidu­al dice are elec­tric­ally and mech­an­ic­ally con­nec­ted to a wafer, often used in advanced pack­aging and 3D integ­ra­tion.


An insu­lat­ing mater­i­al that an applied elec­tric field can polar­ize.

dielectric constant

An older term fre­quently used for rel­at­ive per­mit­tiv­ity. Stand­ards organ­iz­a­tions have deprec­ated this term in favor of rel­at­ive per­mit­tiv­ity due to poten­tial ambiguities.


See dual in-line pack­age.


Com­pon­ents sep­ar­ate or dis­tinct from each oth­er, like res­ist­ors or capa­cit­ors, as opposed to integ­rated cir­cuits.

deep trench capacitor (DTC)

A capa­cit­or integ­rated into a semi­con­duct­or sub­strate by cre­at­ing deep recesses, called trenches, to max­im­ize the sur­face area and, there­fore, the capa­cit­ance in a small foot­print. Also known as trench sil­ic­on capa­cit­ors (TSC) and sil­ic­on capa­cit­ors (SiCap).

Doctor of Philosophy (Ph.D.)

An advanced aca­dem­ic degree that rep­res­ents the highest level of form­al edu­ca­tion in many fields. It is typ­ic­ally pur­sued after com­plet­ing under­gradu­ate (Bachelor’s) and post­gradu­ate (Master’s) degrees, although in some cases, stu­dents can trans­ition dir­ectly from a Bachelor’s to a Ph.D. pro­gram. It is the highest level of degree a stu­dent can achieve. Typ­ic­ally, earn­ing a Ph.D. involves con­duct­ing ori­gin­al research that con­trib­utes new know­ledge or under­stand­ing to a spe­cif­ic field of study. The pro­cess usu­ally includes extens­ive research, com­ple­tion of a dis­ser­ta­tion or thes­is, and suc­cess­ful defense of this work before a pan­el of experts. Ph.D. pro­grams can vary in length but often take sev­er­al years to com­plete and require a deep level of com­mit­ment to study­ing and research­ing a spe­cial­ized area of interest.


Impur­ity atoms are added to a semi­con­duct­or mater­i­al dur­ing a pro­cess referred to as dop­ing to modi­fy its elec­tric­al prop­er­ties. Depend­ing on their atom­ic struc­ture, dopants can intro­duce either extra elec­trons (for n‑type) or cre­ate “holes” (for p‑type) in the semiconductor.


Inten­tion­ally adding spe­cif­ic impur­it­ies, called dopants, into a semi­con­duct­or mater­i­al to modi­fy its elec­tric­al prop­er­ties. Depend­ing on the type of impur­ity added, a semi­con­duct­or can become either n‑type or p‑type. Dop­ing con­trols the con­cen­tra­tion and type of charge car­ri­ers in the mater­i­al, enabling the cre­ation of vari­ous semi­con­duct­or devices.


See deep trench capa­cit­or.

dual in-line package (DIP)

A chip pack­aging scheme with a rect­an­gu­lar hous­ing with two par­al­lel rows of elec­tric­al pins or leads extend­ing from its sides. These pins facil­it­ate the con­nec­tion of the IC to cir­cuit boards.


See elec­tro­lyz­er cell mater­i­al.

electrical conductivity

A mater­i­al that eas­ily allows the flow of elec­tric charge. Metals are a typ­ic­al example of highly con­duct­ive mater­i­als, but cer­tain semi­con­duct­ors can also be con­duct­ive, par­tic­u­larly when doped with impur­it­ies that alter their elec­tric­al properties.

electric field

An invis­ible field that sur­rounds charged particles or objects and extends through­out the space around them. This field exerts elec­tric forces on oth­er charged particles with­in its influ­ence, shap­ing the beha­vi­or of elec­tric charges and their inter­ac­tions. Under­stand­ing elec­tric fields is essen­tial for grasp­ing the dynam­ics of elec­tric­ally charged entities.


A pro­cess that uses an elec­tric cur­rent to reduce dis­solved met­al cations so that they form a thin, coher­ent met­al coat­ing on an elec­trode. This meth­od is com­monly used in indus­tries for plat­ing, refin­ing, and syn­thes­iz­ing mater­i­als. Also known as electroplating.


The branch of chem­istry that deals with the rela­tion­ship between elec­tri­city and chem­ic­al reac­tions. Elec­tro­chem­ic­al pro­cesses involve the move­ment of elec­trons between molecules, often res­ult­ing in a chem­ic­al change.

electrochemical cell

A device that can gen­er­ate elec­tric­al energy from elec­tro­chem­ic­al reac­tions occur­ring in it or use the elec­tric­al energy sup­plied to it to facil­it­ate elec­tro­chem­ic­al reac­tions in it. It typ­ic­ally con­sists of two elec­trodes immersed in an elec­tro­lyte. Bat­ter­ies, fuel cells, and elec­tro­lyz­er cells are com­mon examples of elec­tro­chem­ic­al cells.


An elec­tric­al con­duct­or used to make con­tact with a non­metal­lic part of a cir­cuit (e.g., a semi­con­duct­or or an elec­tro­lyte). See also anode and cath­ode.


An elec­tro­chem­ic­al pro­cess where an elec­tric cur­rent is passed through an elec­tro­lyte to drive a non-spon­tan­eous chem­ic­al reac­tion. See also water elec­tro­lys­is.


A medi­um con­tain­ing ions that are elec­tric­ally con­duct­ing through the move­ment of those ions but not con­duct­ing electrons.


A device that car­ries out elec­tro­lys­is, e.g., is used to split water into hydro­gen and oxygen.

electrolyzer cell

An elec­tro­chem­ic­al cell used in an elec­tro­lyz­er. Elec­tro­lys­is takes place in elec­tro­lyz­er cells.

electrolyzer cell material (ECM)

Gen­er­al term for mater­i­als that are part of an elec­tro­lyz­er cell. The term cov­ers elec­tro­lyte (the pro­ton exchange mem­brane in a PEM elec­tro­lyz­er), cata­lysts (iridi­um in a PEM elec­tro­lyz­er), elec­trodes (anode och cath­ode), por­ous trans­port lay­ers, and bipolar plates.

electrolyzer cell stack

See elec­tro­lyz­er stack.

electrolyzer stack

A col­lec­tion of elec­tro­lyz­er cells assembled togeth­er in a series or par­al­lel con­fig­ur­a­tion to increase the pro­duc­tion capa­city of the elec­tro­lyz­er. Elec­tro­lyz­ers util­ize elec­tro­lyz­er stacks rather than indi­vidu­al elec­tro­lyz­er cells.

electrolyzer test system (ETS)

A spe­cial­ized setup used for eval­u­at­ing and test­ing the per­form­ance of elec­tro­lyz­ers. An elec­tro­lyz­er test sys­tem is designed to sim­u­late vari­ous oper­at­ing con­di­tions and para­met­ers that an elec­tro­lyz­er might encounter in real-world applications.


See elec­tro-depos­ition.

embedded capacitor

A capa­cit­or is embed­ded with­in a prin­ted cir­cuit board (PCB), a sub­strate-like PCB (SLP), or anoth­er sub­strate instead of being moun­ted onto a PCB, SLP, or oth­er sub­strate. Embed­ding capa­cit­ors allows for more effi­cient use of space and can improve the per­form­ance of high-speed circuits.

engineering sample

A pre-pro­duc­tion ver­sion of a future product provided to pro­spect­ive cus­tom­ers for test­ing, feed­back, or mar­ket­ing purposes.

equivalent series inductance (ESL)

A meas­ure of the inher­ent induct­ive react­ance found in real-world capa­cit­ors. While an ideal capa­cit­or is con­sidered to have no induct­ive react­ance, actu­al capa­cit­ors exhib­it some due to their mater­i­als and con­struc­tion. This induct­ive beha­vi­or is rep­res­en­ted as an induct­or in series with the ideal capa­cit­or and is termed the equi­val­ent series inductance.

equivalent series resistance (ESR)

A meas­ure of the inher­ent res­ist­ive losses with­in a real-world capa­cit­or or induct­or. While ideal capa­cit­ors and induct­ors are con­sidered to have no res­ist­ance, actu­al com­pon­ents exhib­it some res­ist­ance due to their mater­i­als and con­struc­tion. This res­ist­ive char­ac­ter­ist­ic is effect­ively rep­res­en­ted as a res­ist­or in series with the ideal com­pon­ent and is termed the equi­val­ent series resistance.


See equi­val­ent series induct­ance.


See equi­val­ent series res­ist­ance.


See the elec­tro­lyz­er test sys­tem.


See farad.


A com­pany that designs semi­con­duct­or devices but relies on third-party man­u­fac­tur­ing facil­it­ies for pro­duc­tion, i.e., does not own its fab­ric­a­tion facilities.

farad (F)

The SI unit of capa­cit­ance.

film catalyst

A thin lay­er of cata­lyt­ic mater­i­al used to facil­it­ate or enhance cer­tain chem­ic­al reac­tions dur­ing the semi­con­duct­or man­u­fac­tur­ing pro­cess. These reac­tions can be essen­tial for pro­cesses like chem­ic­al vapor depos­ition or oth­er growth mechanisms.

flip chip

A meth­od where the die is “flipped” so that its act­ive area faces down­ward, mak­ing dir­ect elec­tric­al con­nec­tions to the sub­strate or pack­age. This is in con­trast to tra­di­tion­al meth­ods where the chip’s act­ive area faces upward, and con­nec­tions are made via wire bonding.


The phys­ic­al space occu­pied by a com­pon­ent on a cir­cuit board or with­in an integ­rated cir­cuit lay­out. This term can describe both the size and shape of the com­pon­ent, as well as its ori­ent­a­tion and place­ment. A smal­ler foot­print gen­er­ally allows for a dens­er pack­ing of com­pon­ents, which can be cru­cial in mini­atur­ized electronics.


Refers to the phys­ic­al shape and size of an elec­tron­ic com­pon­ent. When con­sid­er­ing integ­rat­ing com­pon­ents into products, space con­straints and com­pat­ib­il­ity with oth­er com­pon­ents are crucial.


Describes energy sources, tech­no­lo­gies, or prac­tices not depend­ent on coal, oil, or nat­ur­al gas. Fossil-free altern­at­ives reduce envir­on­ment­al harm, pro­mot­ing a health­i­er plan­et. In the con­text of green hydro­gen, fossil-free sig­ni­fies hydro­gen pro­duc­tion meth­ods that exclude the use of fossil fuels, thereby pro­du­cing clean­er energy. See also car­bon-free and car­bon-neut­ral.

fuel cell

A device that con­verts chem­ic­al energy from a fuel into elec­tri­city through an elec­tro­chem­ic­al reac­tion. It typ­ic­ally con­sists of an anode, a cath­ode, and an elec­tro­lyte. Com­mon fuels include hydro­gen or meth­an­ol, and the most com­mon oxid­ant is oxy­gen from the air. Unlike bat­ter­ies, which store energy, fuel cells con­tinu­ously gen­er­ate elec­tri­city as long as fuel and an oxid­ant are supplied.

gas diffusion layer (GDL)

An elec­tro­lyz­er cell mater­i­al with a por­ous struc­ture designed to facil­it­ate the trans­port of gases, enhan­cing the cell’s per­form­ance. See also the por­ous trans­port lay­er.

global warming

The long-term increase in Earth’s aver­age sur­face tem­per­at­ure is primar­ily due to the high­er con­cen­tra­tions of green­house gases in the atmo­sphere. This warm­ing is primar­ily attrib­uted to human activ­it­ies, par­tic­u­larly the com­bus­tion of fossil fuels. Glob­al warm­ing is a sig­ni­fic­ant driver behind the broad­er changes observed in our cli­mate system.


See gas dif­fu­sion lay­er.

gray hydrogen

See grey hydro­gen.

green hydrogen

Hydro­gen pro­duced using renew­able energy sources like wind, sol­ar, or hydro­elec­tric power. Typ­ic­ally, green hydro­gen is pro­duced with PEM elec­tro­lyz­ers. See also blue hydro­gen, grey hydro­gen, brown hydro­gen, and black hydro­gen.

greenhouse effect

A nat­ur­al pro­cess in which cer­tain gases in the Earth’s atmo­sphere, like car­bon diox­ide and meth­ane, trap heat from the sun. This trapped heat warms the plan­et and makes it hos­pit­able for life. How­ever, human activ­it­ies, espe­cially the burn­ing of fossil fuels, have increased the con­cen­tra­tions of these gases, intensi­fy­ing the green­house effect and lead­ing to a rise in glob­al temperatures.

greenhouse gas

Gases that trap heat in the Earth’s atmo­sphere, con­trib­ut­ing to the green­house effect and, con­sequently, glob­al warm­ing. The primary green­house gases include car­bon diox­ide, meth­ane, nitrous oxide, and flu­or­in­ated gases. Redu­cing the emis­sion of these gases, espe­cially from human activ­it­ies, is cru­cial for slow­ing or revers­ing the impacts of cli­mate change. Pro­mot­ing fossil-free energy and green hydro­gen can help in mit­ig­at­ing these emissions.

grey hydrogen

Hydro­gen gen­er­ated from nat­ur­al gas through pro­cesses such as steam meth­ane reform­ing or auto­therm­al reform­ing, where the car­bon emis­sions are not cap­tured and stored, res­ult­ing in sig­ni­fic­ant car­bon diox­ide emis­sions into the atmo­sphere. See also green hydro­gen, blue hydro­gen, brown hydro­gen, and black hydro­gen.


The syn­thes­is or form­a­tion of mater­i­als, espe­cially crys­tals, under con­trolled conditions.


See henry or hydro­gen.


See hydro­gen gas.


Smoltek’s in-house hydro­gen laboratory.

henry (H)

The SI unit of induct­ance.

heterogeneous integration

The pro­cess of integ­rat­ing dif­fer­ent semi­con­duct­or tech­no­lo­gies into a single sys­tem. This can involve com­bin­ing com­pon­ents of dif­fer­ent mater­i­als or using dif­fer­ent man­u­fac­tur­ing pro­cesses to achieve a sys­tem with optim­ized per­form­ance, func­tion­al­ity, and power efficiency.

high-performance computing (HPC)

A branch of com­put­ing that deals with devel­op­ing and using super­com­puters and par­al­lel pro­cessing tech­niques to solve com­plex com­pu­ta­tion­al prob­lems. High-per­form­ance com­put­ing sys­tems are char­ac­ter­ized by their abil­ity to quickly pro­cess vast amounts of data. They are used in sci­entif­ic research, engin­eer­ing sim­u­la­tions, and data analysis.

homogeneous integration

The integ­ra­tion of semi­con­duct­or devices or sys­tems made from the same mater­i­al sys­tem or pro­cess. It’s about com­bin­ing like with like to achieve a par­tic­u­lar functionality.


See high-per­form­ance com­put­ing.

hydrogen (H)

A chem­ic­al ele­ment with the sym­bol H and atom­ic num­ber 1. It’s a col­or­less, odor­less, and highly flam­mable gas and is the universe’s light­est and most abund­ant ele­ment. At stand­ard con­di­tions, hydro­gen is a gas of H2 molecules.

hydrogen gas

Gaseous hydro­gen con­sist­ing of molecules with two hydro­gen atoms (H2).


See integ­rated cir­cuit.


A meas­ure of the oppos­i­tion a com­pon­ent or cir­cuit presents to the flow of altern­at­ing cur­rent (AC). Imped­ance encom­passes both res­ist­ance and react­ance. It is typ­ic­ally rep­res­en­ted in ohms (Ω) and determ­ines how a com­pon­ent or cir­cuit will respond to an applied AC voltage.


A prop­erty of a com­pon­ent in a cir­cuit that opposes changes in cur­rent flow. It res­ults from the mag­net­ic field gen­er­ated around an elec­tric­al con­duct­or when cur­rent flows through it. Induct­ance is meas­ured in henrys (H). It plays a cru­cial role in AC cir­cuits, espe­cially in fil­ter­ing and energy stor­age applications.


An elec­tron­ic com­pon­ent that stores energy in the form of a mag­net­ic field when elec­tric cur­rent flows through it. Typ­ic­ally con­struc­ted as a coil of wire, its primary prop­erty is induct­ance, which opposes rap­id changes in cur­rent flow. Induct­ors are com­monly used in fil­ter­ing applic­a­tions, energy stor­age, and cir­cuits where mag­net­ic fields are necessary.


A mater­i­al that does not con­duct elec­tri­city. Insu­lat­ors are used to pre­vent the flow of elec­tric current.

integrated circuit (IC)

① Syn­onym­ous with die.

② The final, func­tion­al unit con­sist­ing of one or more dice enclosed in a pro­tect­ive cas­ing. This encap­su­la­tion provides not only phys­ic­al pro­tec­tion but also facil­it­ates extern­al con­nectiv­ity through pins or leads and aids in heat man­age­ment. In this form, the IC is ready for integ­ra­tion into elec­tron­ic systems.

intellectual property (IP)

Refers to cre­ations of the mind, such as inven­tions, lit­er­ary and artist­ic works, designs, sym­bols, names, and images used in com­merce. Intel­lec­tu­al prop­erty is pro­tec­ted by law, allow­ing cre­at­ors or IP hold­ers to earn recog­ni­tion or fin­an­cial bene­fits from what they invent or cre­ate. In com­put­ing, this can include soft­ware code, algorithms, pat­ents on hard­ware designs, trade­marks, and copy­rights on soft­ware applications.


An elec­tric­ally con­duct­ive path that con­nects tran­sist­ors and oth­er elec­tron­ic com­pon­ents in an integ­rated cir­cuit. It can also refer to an elec­tric­ally con­duct­ive path that con­nects a die to the package’s con­nect­ors or two dice.

internet of things (IoT)

A concept wherein every­day objects are embed­ded with sensors, soft­ware, and oth­er tech­no­lo­gies to con­nect and exchange data with oth­er devices and sys­tems over the inter­net. This inter­con­nec­ted­ness allows for more dir­ect integ­ra­tion of the phys­ic­al world into com­puter-based sys­tems, lead­ing to improved effi­ciency, accur­acy, and eco­nom­ic bene­fits. Examples include smart ther­mo­stats, wear­able fit­ness track­ers, and con­nec­ted house­hold appliances.


A sub­strate, often made of sil­ic­on, glass, or organ­ic mater­i­als, that is used in advanced pack­aging. It acts as an inter­me­di­ary lay­er where one or more dice are moun­ted and elec­tric­ally con­nec­ted through intern­al inter­con­nects. These inter­con­nects facil­it­ate com­mu­nic­a­tion between dif­fer­ent dice or trans­ition from a fine pitch on a die to a wider pitch on the pack­age through a Redis­tri­bu­tion Lay­er (RDL). Inter­posers may also integ­rate addi­tion­al func­tion­al­it­ies like capa­cit­ors.


An atom or molecule that has acquired a net elec­tric charge due to the gain or loss of one or more elec­trons. Ions are essen­tial in vari­ous chem­ic­al and elec­tro­chem­ic­al pro­cesses, includ­ing con­duct­ing elec­tri­city in solu­tions and form­ing ion­ic compounds.


See the inter­net of things.


See intel­lec­tu­al prop­erty.


See iridi­um.

iridium (Ir)

A shiny, sil­very-white noble met­al with the sym­bol Ir. Iridi­um is one of the most cor­ro­sion-res­ist­ant metals. It is one of the rarest ele­ments in Earth’s crust, with estim­ated annu­al pro­duc­tion and con­sump­tion of only 7–8 tonnes, mak­ing it very expens­ive. It is the only met­al that can be used in PEM elec­tro­lyz­ers as a cata­lyst.


See joint devel­op­ment agree­ment.

joint development agreement (JDA)

A con­trac­tu­al rela­tion­ship between two or more entit­ies to col­lab­or­ate on a spe­cif­ic pro­ject or ini­ti­at­ive, typ­ic­ally involving research, devel­op­ment, or innov­a­tion. Such agree­ments out­line each party’s respons­ib­il­it­ies, roles, and rights, as well as the alloc­a­tion of any poten­tial rev­en­ues, intel­lec­tu­al prop­erty rights, and oth­er key terms related to the project.

joint venture (JV)

A con­trac­tu­al rela­tion­ship between two or more entit­ies to col­lab­or­ate by pool­ing resources to achieve a spe­cif­ic task or busi­ness goal. In a joint ven­ture, each par­ti­cipant is respons­ible for profits, losses, and costs asso­ci­ated with the ven­ture. How­ever, the enter­prise oper­ates inde­pend­ently from the par­ti­cipants’ oth­er busi­ness interests.

joint venture agreement (JVA)

Agree­ment between two or more parties gov­ern­ing the form­a­tion and oper­a­tion of a joint ven­ture.


See joint ven­ture.


See joint ven­ture agree­ment.


Refers to the side of a semi­con­duct­or pack­age that has inter­con­nect­ors inten­ded for con­nec­tion to a cir­cuit board.

landside capacitor (LSC)

A capa­cit­or attached to the land­side of an integ­rated cir­cuit. When serving as a decoup­ling capa­cit­or, its prox­im­ity to the die allows it to effect­ively main­tain a stable power sup­ply to the integ­rated cir­cuit. Con­straints like sub­strate size and the height of solder balls or con­nec­tions often influ­ence its dimen­sions and form factor.

Letter of Intent (LoI)

A writ­ten doc­u­ment express­ing two or more parties’ inten­tion to enter into a par­tic­u­lar agree­ment. It is often used in busi­ness trans­ac­tions such as mer­gers and acquis­i­tions. While typ­ic­ally not leg­ally bind­ing in terms of the deal itself, it can include bind­ing pro­vi­sions related to con­fid­en­ti­al­ity, exclus­iv­ity, or timelines. An LOI is a pre­curs­or to a form­al con­tract, indic­at­ing ser­i­ous interest from the sender about a par­tic­u­lar action or event.


See low induct­ance chip capa­cit­or.


See let­ter of intent.

Long run tests

Exper­i­ments or eval­u­ations con­duc­ted over an exten­ded peri­od (typ­ic­ally 1,000 hours or more) to assess the per­form­ance, dur­ab­il­ity, and reli­ab­il­ity of a sys­tem, com­pon­ent, or pro­cess. These tests are cru­cial for under­stand­ing how a product or sys­tem behaves under pro­longed use or expos­ure to vari­ous conditions.


The dur­a­tion for which a product, sys­tem, or com­pon­ent is expec­ted to func­tion effect­ively before it requires replace­ment or becomes too inef­fi­cient or unre­li­able to use. It’s a meas­ure of the longev­ity and dur­ab­il­ity of an item under nor­mal oper­at­ing conditions.

low inductance chip capacitor (LICC)

A capa­cit­or designed to have low induct­ance, min­im­iz­ing the unwanted effects of induct­ance in elec­tron­ic cir­cuits. These capa­cit­ors are often used in high-fre­quency applic­a­tions where redu­cing induct­ance is crit­ic­al for main­tain­ing sig­nal integrity.


See land­side capa­cit­or.


See milli.


Mil­li­ampere; see milli and ampere.

make-to-order (MTO)

A man­u­fac­tur­ing strategy where products are pro­duced based on cus­tom­er orders. Instead of main­tain­ing large invent­or­ies, com­pan­ies using MTO pro­cesses man­u­fac­ture goods as orders are received, allow­ing for cus­tom­iz­a­tion and redu­cing excess inventory.

make-to-stock (MTS)

A man­u­fac­tur­ing approach where products are pro­duced in anti­cip­a­tion of cus­tom­er demand and stocked in invent­ory. This strategy is suit­able for products with stable and pre­dict­able demand, allow­ing for faster deliv­ery to customers.


See mem­brane elec­trode assembly.


A thin lay­er of mater­i­al that serves a spe­cif­ic func­tion in elec­tro­chem­ic­al cells, such as bat­ter­ies, fuel cells, and elec­tro­lyz­ers. A mem­brane acts as a phys­ic­al bar­ri­er between dif­fer­ent com­part­ments of the cell, like sep­ar­at­ing the anode and cath­ode in an elec­tro­lyz­er, select­ively allow­ing cer­tain ions or molecules to pass through while block­ing oth­ers. While allow­ing ions to pass, mem­branes also provide elec­tric­al insu­la­tion between the two sides of the cell.

membrane electrode assembly (MEA)

A pre-assembled part used in fuel cells, PEM elec­tro­lys­ers and AEM elec­tro­lys­ers. In the middle, there is a mem­brane ( PEM or AEM). One side is called the anode side, and the oth­er is called the cath­ode side, depend­ing on wheth­er they are con­nec­ted to the pos­it­ive or neg­at­ive ter­min­al of a power source. Adja­cent to the sides of the mem­brane is a cata­lyst. A PEM elec­tro­lyz­er uses iridi­um on the anode side and plat­in­um on the cath­ode side. At the end of each side is a por­ous trans­port lay­er that allows water and gas to be trans­por­ted to or from the mem­brane and cata­lyst, depend­ing on the function.

memorandum of understanding (MoU)

A form­al but non-bind­ing agree­ment between two or more parties out­lining the terms and details of an under­stand­ing, includ­ing the require­ments and respons­ib­il­it­ies of each party. It can include bind­ing pro­vi­sions related to con­fid­en­ti­al­ity, exclus­iv­ity, or timelines. An MoU is often used in situ­ations where parties either don’t imply a leg­al com­mit­ment or in situ­ations where the parties can­not cre­ate a leg­ally enforce­able agree­ment. It serves as a guide to the expect­a­tions and is often a pre­curs­or to a form­al contract.

metal-insulation-metal capacitor (MIM capacitor)

A type of capa­cit­or struc­ture where a dielec­tric mater­i­al is sand­wiched between two met­al lay­ers, com­monly used with integ­rated cir­cuits.

micro (µ)

A pre­fix indic­at­ing one-mil­lionth (10-6) of a unit, such as a micro­second or a micrometer.


See integ­rated cir­cuit.

milli (m)

A pre­fix indic­at­ing one-thou­sandth (10-3</) of a unit, such as a mil­li­gram (mg) or a mil­li­meter (mm).


See met­al-insu­la­tion-met­al.


See multi-lay­er ceram­ic capa­cit­or.

Moore’s law

An obser­va­tion made by Gor­don Moore in 1965 which pre­dicts that the num­ber of tran­sist­ors on a chip will double approx­im­ately every two years, lead­ing to expo­nen­tial increases in com­put­ing power and decreases in cost per transistor.


MOSFET is a met­al-oxide-semi­con­duct­or field-effect tran­sist­or. It is a type of tran­sist­or often used in elec­tron­ic cir­cuits for amp­li­fic­a­tion and switch­ing pur­poses. It is known for its high effi­ciency, fast switch­ing speeds, and com­pact size. MOS­FETs have three ter­min­als: gate, source, and drain. By apply­ing a voltage to the gate ter­min­al, an elec­tric field is cre­ated, allow­ing or block­ing the flow of cur­rent between the source and drain ter­min­als. Due to their low power con­sump­tion and high-speed switch­ing cap­ab­il­it­ies, MOS­FETs are found­a­tion­al com­pon­ents in digit­al integ­rated cir­cuits.


See memor­andum of under­stand­ing.


See make-to-order.


See make-to-stock.

multi-layer ceramic capacitor (MLCC)

A type of capa­cit­or con­struc­ted with mul­tiple lay­ers of dielec­tric and met­al lay­ers, res­ult­ing in a com­pact struc­ture with high capa­cit­ance.

Mil­liohm; see milli and ohm.


See nano.


Refers to a semi­con­duct­or in which the major­ity of charge car­ri­ers are elec­trons. This is achieved by intro­du­cing dopants into the semi­con­duct­or mater­i­al with few­er valence elec­trons than the mater­i­al itself. The “n” stands for neg­at­ive, indic­at­ing the electron’s neg­at­ive charge.

nano (n)

A pre­fix indic­at­ing one-bil­lionth (10-9) of a unit, such as a nano­second or nanometer.


A fiber with a dia­met­er on the nano­scale. Due to their minute size, nan­ofibers pos­sess high sur­face area-to-volume ratios, lead­ing to enhanced mater­i­al prop­er­ties that dif­fer sig­ni­fic­antly from those of their bulk counterparts.


The scale of meas­ure­ment at the nano­met­er level. A nano­met­er (nm) is a unit of length equal to one bil­lionth of a meter. When some­thing is described as being on the nano­met­er scale, it typ­ic­ally means that its dimen­sions or fea­tures are less than 100 nanometers.


A struc­ture with at least one dimen­sion in the nano­scale. These struc­tures often exhib­it phys­ic­al and chem­ic­al prop­er­ties dis­tinct from bulk mater­i­als due to their small size and high sur­face area.


See the non-dis­clos­ure agree­ment.


Nan­o­farad; see nano and farad.


Nano­met­er; see nano.

non-disclosure agreement (NDA)

A leg­ally bind­ing con­tract between two or more parties that estab­lishes a con­fid­en­tial rela­tion­ship. The agree­ment spe­cifies that cer­tain inform­a­tion shared between the parties must not be dis­closed to third parties. Often used in busi­ness set­tings when pro­pri­et­ary inform­a­tion, trade secrets, or sens­it­ive data is shared, the non-dis­clos­ure agree­ment ensures that such details remain con­fid­en­tial and are not used for any pur­pose oth­er than what’s out­lined in the agree­ment. Viol­at­ing the terms can res­ult in leg­al penalties.

ohm (Ω)

The SI unit for meas­ur­ing res­ist­ance in elec­tric­al com­pon­ents.


See pico.


Refers to a semi­con­duct­or in which the major­ity of charge car­ri­ers are “holes” (miss­ing elec­trons, cre­at­ing a pos­it­ive charge). This is achieved by intro­du­cing dopants into the semi­con­duct­or mater­i­al with few­er valence elec­trons than the mater­i­al itself. The “p” stands for pos­it­ive, indic­at­ive of the pos­it­ive charge of the hole.

p–n junction

A bound­ary or inter­face between two regions of a semi­con­duct­or material—one doped with pos­it­ive charge car­ri­ers ( p‑type) and the oth­er doped with neg­at­ive charge car­ri­ers ( n‑type). The p–n junc­tion is a fun­da­ment­al com­pon­ent in semi­con­duct­or devices. When a voltage is applied across the junc­tion in a spe­cif­ic dir­ec­tion, it allows cur­rent to flow (for­ward bias). In the oppos­ite dir­ec­tion, it blocks the cur­rent flow (reverse bias). This beha­vi­or is cru­cial for the func­tion­al­ity of diodes, tran­sist­ors, and oth­er semi­con­duct­or devices in elec­tron­ic circuits.


See semi­con­duct­or pack­aging.


An exposed region of met­al on a sub­strate, such as a cir­cuit board or a die, to which an elec­tric­al inter­con­nects to anoth­er device or sys­tem is created.

passive component

A com­pon­ent that does not require an extern­al power source to oper­ate and does not amp­li­fy sig­nals. Pass­ive com­pon­ents can store, fil­ter, or dis­sip­ate energy. Examples include res­ist­ors, capa­cit­ors, and induct­ors.

pattern catalyst

A cata­lyst that is select­ively placed or formed in spe­cif­ic pat­terns, typ­ic­ally on a sub­strate or sur­face. This pat­terned arrange­ment can be vital in pro­cesses like grow­ing car­bon nan­ofibers, as it dic­tates the growth sites and dir­ec­tion­al­ity of the nan­ofibers.


See cir­cuit board.


See plasma-enhanced chem­ic­al vapor depos­ition.


See pro­ton exchange mem­brane.

PEM electrolysis

See pro­ton exchange mem­brane elec­tro­lys­is.

PEM electrolyzer

See pro­ton exchange mem­brane elec­tro­lyz­er.

PEM water electrolysis

See pro­ton exchange mem­brane elec­tro­lys­is.

PEM water electrolyzer

See pro­ton exchange mem­brane water elec­tro­lyz­er.


See abso­lute per­mit­tiv­ity.


① A scale used to spe­cify the acid­ity or basi­city of an aqueous solution.

② Pico­henry; see pico and henry.


See Doc­tor of Philo­sophy.

pico ℗

A pre­fix indic­at­ing one-tril­lionth (10-12) of a unit, such as a pico­second or picometer.


A con­nect­or designed as a pin inten­ded to be soldered into holes on a cir­cuit board.


One of the four fun­da­ment­al states of mat­ter, along­side sol­id, liquid, and gas. It is char­ac­ter­ized by the elec­trons being sep­ar­ated from their par­ent atoms or molecules. This sep­ar­a­tion of charged particles gives plasma unique prop­er­ties, includ­ing elec­tric­al con­duct­iv­ity and the abil­ity to respond to elec­tro­mag­net­ic fields.

plasma enhanced chemical vapor deposition (PECVP)

A pro­cess used to depos­it thin film mater­i­als from a gas state (vapor) to a sol­id state on a sub­strate. The pro­cess util­izes plasma to reduce the required tem­per­at­ure com­pared to stand­ard chem­ic­al vapor depos­ition (CVD).

platinum (Pt)

Plat­in­um (Pt) is a shiny, sil­very-white met­al with the sym­bol Pt. Known for its remark­able res­ist­ance to cor­ro­sion and high melt­ing point, plat­in­um is a highly dur­able noble met­al. It is rel­at­ively scarce in the Earth’s crust, con­trib­ut­ing to its high value and cost. In the realm of pro­ton exchange mem­brane (PEM) fuel cells and elec­tro­lyz­ers, plat­in­um plays a cru­cial role as a cata­lyst, par­tic­u­larly on the cath­ode side, where it effi­ciently facil­it­ates the reduc­tion of oxy­gen in fuel cells and the pro­duc­tion of hydro­gen in electrolyzers.

polarization curve

A graph­ic­al rep­res­ent­a­tion of the voltage versus cur­rent of an elec­tro­chem­ic­al cell, which provides inform­a­tion about the per­form­ance and effi­ciency of the cell.


The phe­nomen­on where there is a sep­ar­a­tion or shift in the cen­ters of pos­it­ive and neg­at­ive charges with­in a mater­i­al leads to an intern­al elec­tric dipole. This can be induced by an extern­al elec­tric field or as an inher­ent prop­erty of the mater­i­al. The extent of this sep­ar­a­tion determ­ines the material’s polar­iz­ab­il­ity, which influ­ences vari­ous elec­tric­al prop­er­ties, such as capa­cit­ance and per­mit­tiv­ity.

porous transport electrode (PTE)

An elec­trode with a por­ous trans­port lay­er. The term is used in PEM elec­tro­lyz­ers to include the cata­lyst depos­ition on the elec­trode in con­trast to the MEA, where the cata­lyst is usu­ally coated on the PEM membrane.

porous transport layer (PTL)

An elec­tro­lyz­er cell mater­i­al with a por­ous struc­ture designed to facil­it­ate the trans­port of gases or liquids, enhan­cing the cell’s performance.

power rails

Lines or tracks in an elec­tron­ic cir­cuit that deliv­er power to the com­pon­ents of the circuit.


Start­ing mater­i­als that under­go a change to pro­duce some­thing else. In the con­text of chem­ic­al vapor depos­ition and plasma-enhanced chem­ic­al vapor depos­ition, pre­curs­ors are the spe­cif­ic gases or vapors intro­duced into the reac­tion cham­ber that will react to form the desired sol­id mater­i­al on a surface.

printed circuit board (PCB)

See cir­cuit board.

proton exchange membrane (PEM)

A syn­thet­ic poly­mer mem­brane that is a sol­id-state elec­tro­lyte, often used in PEM-elec­tro­lyz­ers for water elec­tro­lys­is and fuel cells.

proton exchange membrane electrolysis

Elec­tro­lys­is char­ac­ter­ized by hav­ing elec­trodes on each side of a pro­ton exchange mem­brane.

proton exchange membrane electrolyzer

An elec­tro­lyz­er using a pro­ton exchange mem­brane. This device is employed for the pro­duc­tion of hydro­gen through water elec­tro­lys­is. The pro­ton exchange mem­brane plays a pivotal role by allow­ing pro­tons to pass through while block­ing elec­trons, facil­it­at­ing the sep­ar­a­tion of hydro­gen and oxy­gen from water. PEM-elec­tro­lyz­ers are util­ized in vari­ous indus­tries, includ­ing energy and man­u­fac­tur­ing, for gen­er­at­ing green hydro­gen, a valu­able resource in pur­su­ing sus­tain­able and envir­on­ment­ally friendly prac­tices. A massive indus­tri­al scale-up of pro­duc­tion of PEM elec­tro­lyz­ers is ongo­ing to meet the needs of the extremely fast-grow­ing green hydro­gen market.

proton exchange membrane water electrolysis (PEMWE)

Elec­tro­lys­is using a pro­ton exchange mem­brane elec­tro­lyz­er to split water into hydro­gen and oxy­gen. Its main advant­ages are rap­id adapt­a­tion to fluc­tu­ations in elec­tri­city sup­ply, high energy effi­ciency, and very clean hydro­gen. How­ever, the main dis­ad­vant­age is the use of iridi­um as a cata­lyst; iridi­um is a rare and expens­ive metal.

proton exchange membrane water electrolyzer

Pro­ton exchange mem­brane elec­tro­lyz­er built for the pur­pose of water elec­tro­lys­is. See also pro­ton exchange mem­brane water elec­tro­lys­is.


See plat­in­um.


See por­ous trans­port elec­trode.


See por­ous trans­port lay­er.

raman spectroscopy

A tech­nique used to study the makeup and char­ac­ter­ist­ics of mater­i­als by shin­ing a laser light on them and observing how the wavelength shifts in scattered light. The shif­ted intens­ity can reveal inform­a­tion about the molecules in the mater­i­al. This meth­od is widely used to identi­fy sub­stances and under­stand their properties.


See the redis­tri­bu­tions lay­er.


A com­pon­ent of imped­ance that expli­citly rep­res­ents oppos­i­tion to changes in altern­at­ing cur­rent (AC) due to either capa­cit­ance or induct­ance. React­ance does not dis­sip­ate energy as induct­ance does. Instead, it res­ults in a phase shift between voltage and cur­rent in an AC cir­cuit. It’s meas­ured in ohms (Ω) and can be either capa­cit­ive (neg­at­ive react­ance) or induct­ive (pos­it­ive reactance).

redistribution layer (RDL)

A lay­er in advanced pack­aging of semi­con­duct­ors that reroutes and redis­trib­utes elec­tric­al con­nec­tions from the ini­tial lay­out to a dif­fer­ent layout.

relative permittivity

The ratio of a material’s abso­lute per­mit­tiv­ity (ε) to the abso­lute per­mit­tiv­ity of a vacu­um (ε0). It is often denoted εr or κ. Rel­at­ive per­mit­tiv­ity is a dimen­sion­less quant­ity and provides a com­par­at­ive meas­ure of how well a mater­i­al can become polar­ized in response to an elec­tric field rel­at­ive to the abso­lute per­mit­tiv­ity of a vacuum.


A prop­erty of a com­pon­ent in a cir­cuit that quan­ti­fies the loss in flow of elec­tric cur­rent, res­ult­ing in the con­ver­sion of elec­tric­al energy into heat. Res­ist­ance is quan­ti­fied in ohms (Ω) and is a fun­da­ment­al concept in elec­tron­ic cir­cuits, determ­in­ing how much a com­pon­ent or mater­i­al will res­ist the cur­rent flow.


An elec­tron­ic com­pon­ent designed to intro­duce a spe­cif­ic amount of res­ist­ance into a cir­cuit, thereby lim­it­ing or con­trolling the flow of elec­tric cur­rent.


① A mater­i­al whose elec­tric­al con­duct­iv­ity lies between that of con­duct­ors (like metals) and insu­lat­ors (like glass). Semi­con­duct­ors can con­duct more elec­tri­city by dop­ing, mak­ing them essen­tial for mod­ern elec­tron­ics. Devices like tran­sist­ors, diodes, and integ­rated cir­cuits are built using semi­con­duct­ors. Com­mon semi­con­duct­or mater­i­als include sil­ic­on and gal­li­um arsenide.

② In com­mon par­lance, it may also refer to com­pon­ents, usu­ally integ­rated cir­cuits, made from semi­con­duct­or materials.

③ In com­mon par­lance, it may also refer to the industry pro­du­cing semi­con­duct­or components.

semiconductor packaging

The pro­cess of enclos­ing or encap­su­lat­ing a die or dice to provide mech­an­ic­al sup­port, pro­tect from phys­ic­al dam­age, dis­sip­ate heat, and provide elec­tric­al con­nec­tions. Examples of elec­tric­al con­nec­tions are dual in-line pack­age (DIP), ball grid array (BGA), and chip-on-board (COB).

silicon capacitor (SiCap)

See deep trench capa­cit­or.


See deep trench capa­cit­or.


See sys­tem-in-pack­age.


See sub­strate-like PCB.


See sur­face-moun­ted device.


Smoltek’s trade­mark for a pro­pri­et­ary tech­no­logy to grow car­bon nan­ofibers in pre­cisely defined patterns.

Smoltek ECM

Smoltek’s trade­mark for a por­ous trans­port lay­er enhanced with car­bon nan­ofibers covered by an atom­ic lay­er of plat­in­um for cor­ro­sion pro­tec­tion and with iridi­um atoms on the outside.


See sys­tem-on-chip.

solder ball

A con­nect­or shaped like a ball inten­ded to be soldered to a pad on a cir­cuit board or anoth­er sub­strate.

solder bump

See solder balls.

solid-state electrolyte (SSE)

An elec­tro­lyte that is in a sol­id form.


Sput­ter­ing is a meth­od where atoms are ejec­ted from a sol­id or liquid tar­get mater­i­al due to the bom­bard­ment of the tar­get by ener­get­ic particles, typ­ic­ally ions of an inert gas like argon. The dis­lodged atoms con­dense onto a nearby sub­strate, form­ing a thin film. This tech­nique is com­monly used in indus­tries such as elec­tron­ics for depos­it­ing metals or con­duct­ive films onto surfaces.


The under­ly­ing mater­i­al or lay­er often serving as a base on which pro­cesses occur or mater­i­als are depos­ited, espe­cially in elec­tron­ics and semi­con­duct­ors.

substrate-like PCB (SLP)

An advanced type of PCB that closely mim­ics the prop­er­ties of a semi­con­duct­or sub­strate, offer­ing enhanced elec­tric­al per­form­ance and mini­atur­iz­a­tion cap­ab­il­it­ies. Char­ac­ter­ized by their ultra-fine line and space widths, typ­ic­ally below 25 micro­met­ers, SLPs enable the integ­ra­tion of more com­pon­ents on a smal­ler sur­face area, mak­ing them ideal for com­pact, high-per­form­ance elec­tron­ic devices.

surface-mounted device

An elec­tron­ic com­pon­ent designed to be moun­ted and soldered dir­ectly onto the sur­face of a cir­cuit board or oth­er substrate.

system-in-package (SiP)

A semi­con­duct­or pack­age that con­tains mul­tiple com­pon­ents, such as pro­cessors, memory, and capa­cit­ors, in a single pack­age allow­ing for a more com­pact and integ­rated solution.

system-on-chip (SoC)

An integ­rated cir­cuit that con­sol­id­ates the neces­sary elec­tron­ic cir­cuits of vari­ous com­puter com­pon­ents on a single chip. Well-known examples are pro­cessors for com­puters or mobile phones, which have ded­ic­ated func­tions for graph­ic pro­cessing (GPU), cent­ral pro­cessing (CPU), cache memory, neur­al engines, and the like, all integ­rated on a single chip.

titanium (Ti)

A strong, lus­trous met­al with a sil­very-gray appear­ance and the chem­ic­al sym­bol Ti. Renowned for its excep­tion­al strength-to-weight ratio, titani­um is highly res­ist­ant to cor­ro­sion, even in sea­wa­ter. It is the ninth most abund­ant ele­ment in the Earth’s crust, but its extrac­tion and pro­cessing are chal­len­ging, which con­trib­utes to its value. In the con­text of elec­tro­chem­ic­al applic­a­tions, titani­um is not typ­ic­ally used as a cata­lyst in PEM elec­tro­lyz­ers.[b]

through-silicon vias (TSV)

Ver­tic­al elec­tric­al con­nec­tions that pass com­pletely through a sil­ic­on wafer or die. Through-sil­ic­on vias are used to con­nect the front and back sides of a wafer or die, enabling the 3D integ­ra­tion of semi­con­duct­or com­pon­ents.


A semi­con­duct­or com­pon­ent used to amp­li­fy or switch elec­tron­ic sig­nals and power is fun­da­ment­al to mod­ern elec­tron­ic devices.

trench silicon capacitor (TSC)

See deep trench capa­cit­or.


See deep trench capa­cit­or.

ultra-thin capacitor

A capa­cit­or with an extremely small phys­ic­al thick­ness. A dis­crete ultra-thin capa­cit­or typ­ic­ally has a thick­ness in the range of 100 µm (0.1 mm). They are used in applic­a­tions where space is at a premi­um, like smart­phones and smartwatches.


See volt.

valence band

The energy levels of the valence elec­trons. This band is com­pletely filled with elec­trons in intrins­ic (pure) semi­con­duct­ors at abso­lute zero tem­per­at­ure. When energy is provided (e.g., through heat), elec­trons in the valence band can gain enough energy to jump to the con­duc­tion band, leav­ing behind holes. The move­ment of these elec­trons and holes under an elec­tric field enables semi­con­duct­ors to con­duct electricity.

valence electron

An elec­tron in the out­er­most shell of an atom. These elec­trons determ­ine an atom’s chem­ic­al prop­er­ties and its abil­ity to bond with oth­er atoms. In the con­text of semi­con­duct­ors, the beha­vi­or of valence elec­trons plays a crit­ic­al role in determ­in­ing the con­duct­iv­ity of the mater­i­al, espe­cially when dopants are introduced.


A term describ­ing sub­stances that can quickly turn into a gas or vapor. For example, water is volat­ile because it evap­or­ates eas­ily when heated.

volt (V)

The SI unit of elec­tric­al poten­tial energy and voltage. One volt is equi­val­ent to one joule of elec­tric poten­tial energy per cou­lomb of charge.


The dif­fer­ence in elec­tric­al poten­tial energy. It acts as an elec­tric­al pres­sure that drives the elec­tric cur­rent in a cir­cuit. It is meas­ured in volts.


See wafer-to-wafer.


A thin slice of semi­con­duct­or, such as sil­ic­on, used for the fab­ric­a­tion of integ­rated cir­cuits.

wafer bonding

A pro­cess for join­ing two wafers togeth­er dir­ectly or using an inter­me­di­ate lay­er. This tech­nique can be used for cre­at­ing com­plex multi-layered semi­con­duct­or struc­tures or devices.

wafer level package (WLP)

A type of semi­con­duct­or pack­aging where the pack­aging pro­cess is applied dir­ectly at the wafer level, rather than to indi­vidu­al die after the wafer has been diced. This can res­ult in a more com­pact and cost-effect­ive pack­age com­pared to tra­di­tion­al pack­aging methods.

wafer-to-wafer (W2W)

A pro­cess in which entire wafers are bon­ded or aligned to one anoth­er, often used in advanced pack­aging and 3D integ­ra­tion.

water electrolysis

Elec­tro­lys­is of water for the pur­pose of split­ting water into hydro­gen and oxygen.

water electrolyzer

An elec­tro­lyz­er used to split water into hydro­gen and oxygen.

wire bonding

A tech­nique that uses thin wires, often made of gold or alu­min­um, to cre­ate elec­tric­al inter­con­nects, typ­ic­ally between a die and a cir­cuit board.

year-over-year (YoY)

A com­par­is­on of a stat­ist­ic or met­ric between two con­sec­ut­ive years. It’s used to see if some­thing has grown, shrunk, or stayed the same from one year to the next, typ­ic­ally shown as a percentage.


See year-over-year.


See abso­lute per­mit­tiv­ity.


See rel­at­ive per­mit­tiv­ity.


See rel­at­ive per­mit­tiv­ity.


See rel­at­ive per­mit­tiv­ity.


See micro.


Micro­farad; see micro and farad.


See ohm.