Nanowires fabrication - 2
Self-Assembly and Deep Reactive Ion Etching
Today we are introducing the last nanofabrication method adopted at INRiM to nanofabricate large arrays of Silicon Nanowires: nanospheres self-assembly and Deep Reactive Ion Etching.
The approach is using the supramolecular self-assembly to obtain a nanosphere nanolitography on large area, coupled with Deep Reactive Ion Etching at low temperature with the Oxford PlasmaLab 100 cobra
STEP 1 - Deposition of nanospheres.
On a clean and functionalised silicon substrate, with piraña solution (H2SO4:H2O2 3:1) or oxygen plasma, in order to render hydrophilic the silicon surface, the colloidal suspension is spun, forming a monolayer of polystyrene nanospheres arranged in hexagonal close packed manner.
STEP 2 - Reduction and control of nanospheres.
After self-assembly by spinning, the original sphere diameter is reduced in oxygen plasma. The initial sphere diameter will determine the periodicity of the array, the final sphere diameter will determine the nanowires diameter.
STEP 3 - Silicon dioxide DRIE.
Once the nanospheres has been reduced, Deep Reactive Ion Etching at low temperature is applied to the 80 nm of thermal silicon dioxide passivating the silicon wafer.
STEP 4 - Silicon nanowires DRIE.
After silicon dioxide etching, Deep Reactive Ion Etching at low temperature is then applied to etch silicon nanowires with the desired length and aspect ratio
The INRiM Oxford PlasmaLab 100 Cobra and Jiushuai Xu, from TU Braunschweig during his recent visit at QR Labs INRiM.