Wet Chemical Etching of InP for Cleaning Applications

Abstract

A study of the wet chemical etching of InP has been used to develop an oxide formation/oxide dissolution (OFOD) model that allows for ESH acceptable cleaning of InP in both acidic and alkaline solution. Using this approach toxic PH3 formation is prevented and a smooth surface finish is obtained. Mixtures for post-CMP treatment of InP (100) surfaces with a target etch rate of 1–2 nm/min have been proposed. Due to minimal substrate loss, the etch rates were determined by the use of Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). Optimal conditions were found for 0.25 M H2O2/1 M HCl and 0.75 M H2O2/1 M H2SO4. After exposing various crystal orientations to these mixtures, it was shown that the largest degree of anisotropy is achieved for H2O2/H2SO4.