A simple and efficient method for preparing silicon nanopit arrays

Abstract

This article presents a simple and efficient method for preparing silicon nanopit arrays structure using laser interference lithography (LIL). Highly ordered nanopit arrays in two dimensions were fabricated on 2 inch Si (001) substrate by LIL and in combination with dry etching and wet etching processes. Dot arrays were directly etched to nanopit arrays with this method, which omitted the necessary steps of metal deposition and lift off in pattern reversal process. Forming a fluorocarbon organic polymer layer on silicon surface after dry etching, which can be used as a wet etching mask, and producing a thin silicon mesa layer under the SiO2 dot arrays by slight over-etching in dry etching process, are two key steps for this method. SEM images show the uniform and controllable pit arrays were prepared; the period of the arrays is 450 nm, the length of the pit is 200280 nm. The pit arrays are composes of square and inverted pyramids, and the four facets of the inverted pyramid correspond to four crystal planes (111) of Si substrate.