Atomic scale study of InP etching by Cl₂-Ar ICP plasma discharge

Abstract

A gas phase kinetic model combined to a 3D atomic etching model have been developed to study the etching process of InP under Cl₂-Ar ICP plasma discharge. A gas phase global kinetic model is used to calculate the reactive particle fluxes implied in the etching mechanisms. The 3D atomic InP etching model is based on the Monte Carlo kinetic approach where the plasma surface interactions are described in the probability way. The coupling between the plasma chemistry model and the surface etching model is an interesting approach to predict the etched surface properties in terms of the etch rate, the surface roughness and surface steochiometry as a function of the operating conditions. A satisfactory agreement is obtained by comparing the experimental and the simulation results concerning the evolution of the main plasma discharge parameters such as the electron density and temperature versus the ICP source power for a surface recombination coefficient of atomic chlorine fixed at γ_Cl = 0.04. On the other hand, simulation results show the effect of the operating conditions on the etched surface roughness and the etch rate evolutions with time in the early stage. Moreover, the simulation results show the correlation between the decrease of the ion to chlorine flux ratio and the decrease of the RRMS as a function of the pressure.