Optimization of metal-assisted chemical etching process in fabrication of p-type silicon wire arrays

The metal-assisted chemical etching (MCE) has attracted great attention because of the advantages such as simple and large area process, low-cost and compatible with existing semiconductor technology. We have achieved optimization conditions about two kinds of MCE method for fabrication of p-type silicon wire arrays. First one is one-step MCE that used AgNO3 and BOE solution and second is two-step MCE in which silicon etching proceeds by BOE and H2O2 solution after depositing Au by thermal evaporation. Particularly, the effect of etching parameters, such as etching time and AgNO3 concentration in one-step MCE and metal catalyst thickness and etching solution temperature in two-step MCE on fabrication of silicon was investigated a morphology, length and etch rate of silicon wire. Finally, we have found important factors for fabrication of uniform and well aligned p-type silicon wire by MCE.

► Etch rate of p-type silicon wire on the one-step MCE is a 385 μm/M and 0.072 μm/min. ► Difference thickness of Au metal catalyst on the two-step MCE is fabricated various p-type silicon shapes like nano/micro wire, micro wire, crater and 3D structure. ► Therefore, we were quantitatively presented for difference shape of p-type silicon wire on one-step MCE using AgNO3 and two-step MCE using Au deposition.