Three-dimensional electron probe roughness analysis of InP sidewalls processed by reactive ion beam etching

Abstract

A quantitative three-dimensional measurement of sidewall roughness of InP etched by chlorine-based reactive ion beam etching (RIBE) is presented. An electron probe surface roughness analyzer using four secondary electron detectors was employed. The minimum value of average sidewall roughness under the optimized etching condition was as small as 1 nm, where the etching condition was an ion extraction voltage of 400 V and a Cl2 gas pressure of 1.2×10−3 Torr. It is found that the etched sidewall roughness can be reduced by lowering ion extraction voltage with a relatively higher gas pressure.