On-Chip Integrated Solid-State Micro-Supercapacitor

Research paper pub­lished in the pro­ceed­ings of 2017 IEEE 67th Elec­tron­ic Com­po­nents and Tech­nol­o­gy Con­fer­ence (ECTC), 2017, pp. 173–178.

Fol­low­ing the trend of elec­tron­ic device minia­tur­iza­tion, on-chip inte­grat­ed sol­id-state micro-super­cap­caitors (MS) were fab­ri­cat­ed based on ver­ti­cal­ly aligned car­bon nanofibers (VAC­N­Fs) as elec­trode mate­ri­als and poly­mer­ic gel elec­trolyte as the sol­id elec­trolyte. The VAC­N­Fs were grown at 390 °C and 550 °C tem­per­a­ture on inter­dig­i­tat­ed micro-pat­terns, where the dimen­sions of the dig­its were kept the same but the gap between the dig­its var­ied from 10–100 μm. A max­i­mum capac­i­tance of 1 mF/​cm2 and 0.53mF/cm2 (com­bined foot­print area of dig­its and gaps) were mea­sured for devices with CNFs grown at 390 °C and 20 μm gap, for 550 °C and 10 μm gap, respec­tive­ly. These capac­i­tances are an order of mag­ni­tude high­er than the one for sol­id dielec­tric based sil­i­con trench­es capac­i­tors. The low tem­per­a­ture MS show an inverse capac­i­tance rela­tion with the gap size where­as high tem­per­a­ture shows ran­dom behav­ior. High char­ac­ter­is­tic fre­quen­cies at 45° phase angle are 114 Hz for 100 μm gap and 142 Hz 30 μm gap for 390 °C and 550 °C tem­per­a­tures. A mod­el for the inter­dig­i­tat­ed capac­i­tors was devel­oped and the results showed that by elim­i­nat­ing the cur­rent col­lec­tor resis­tances the char­ac­ter­is­tic fre­quen­cies can be increased to 965 Hz and 866 Hz from 67 Hz and 127 Hz for 10 μm gap pat­terns for 390 °C and 550 °C tem­per­a­tures. The entire fab­ri­ca­tion was done using CMOS com­pat­i­ble process­es thus enabling inte­gra­tion direct­ly on active CMOS chip.

Related insights from Smoltek

Miniaturized capacitors with carbon nanofibers

Smoltek has devel­oped the world’s thinnest dis­crete capac­i­tor. Its total build­ing height is less than thir­ty microm­e­ters (30 µm). You have to stack ten of them on top of each oth­er to reach the same height as today’s indus­try-stan­dard when it comes to sur­face-mount­ed capac­i­tors. The capac­i­tor itself, with­out encap­su­la­tion, is a mere 0.5 to 10 µm. It...
Hand held circular disc with Smoltek logo

Smoltek—from carbon nanofibers to mind-controlled robotic prostheses

Smoltek holds unique world patents for technologies that make material engineering on an atomic level possible. Smoltek has solutions that allow continued miniaturization and increased performance of semiconductors, contribute to carbon-free steel production and renewable energy storage, and enable mind control of robotic prostheses. This is a story of how Smoltek came to be.

Published paper in Solid-State Electronics

We are happy to announce that our paper "Integrated on-chip solid state capacitor based on vertically aligned carbon nanofibers, grown using a CMOS temperature compatible process" is published in the academic journal Solid-State Electronics.

Smoltek patent No. 60 now granted

Smoltek’s proprietary platform keeps growing as we have been awarded another approved patent. This new US patent covers energy storage devices and the usage of the same. Our patent portfolio now comprises 60 granted patents.

Carbon nanofibers (CNFs)

Car­bon nanofibers is a super­ma­te­r­i­al. It is stronger, more elas­tic, and lighter than steel. It con­ducts heat and elec­tric­i­ty bet­ter than met­als. And it can be used to thou­sand­fold the sur­face of mate­ri­als. Let’s take a clos­er look at these tiny fellows. What is a carbon nanofiber (CNF)? A car­bon nanofiber (CNF) is a car­bon-made mate­r­i­al so thin that...