Monte Carlo Simulation of wet etching of silicon: Investigation of (111) surface properties

The etching rate of the Si surface family is of prime importance for micro-fabrication. However, the experimental values of the corresponding etch rate are often scattered and the etching mechanism of surfaces remains unclear. In this paper the Monte Carlo simulation results obtained from etching of Si(111) small size substrates are presented. Simulations were carried out to simulate the behaviour of the surface in contact with strong base aqueous solutions (R - OH). Simulation shows that when etching a small substrate (200 A X 200 A), the etch depth against time curve shows a constant part and a linear part. The former is related to the magnitude of Monte Carlo time steps while the latter corresponds to the evacuation of one sublayer. However, the substrate size fails to impact the etching mechanism which remains unchanged even for an infinite size. The same remark applies to roughness which exhibits a series of alternative peaks.