Nano fabricated silicon nanorod array with titanium nitride coating for on-chip supercapacitors

• High aspect ratio silicon nanorod array as scaffold for favorable ion diffusion electrode of supercapacitors
• Nano layer TiN coating conformally on the silicon nanorod array as the active material
• Cyclic DRIE technology developed to fabricate the silicon nanorod array.
• ALD process developed to coat TiN nano layer on the silicon nanorod array.
• Device of the proof of concept achieves improved specific capacitance, high rate capability and cycling stability.

We demonstrate high aspect ratio silicon nanorod arrays by cyclic deep reactive ion etching (DRIE) process as a scaffold to enhance the energy density of a Si-based supercapacitor. By unique atomic layer deposition (ALD) technology, a conformal nanolayer of TiN was deposited on the silicon nanorod arrays as the active material. The TiN coated silicon nanorods as a supercapacitor electrode lead to a 6 times improvement in capacitance compared to flat TiN film electrode.