Simple Kinetic Model of ECR Reactive Ion Beam Etching Reactor for the Optimization of GaAs Etching Process

Abstract

In order to efficiently optimize electron cyclotron resonance/reactive ion beam etching (ECR-RIBE) process for GaAs, we studied the kinetic mechanism of the process. First we examined the relationship between etching performances and process parameters. We paid particular attention to the effect of the Cl2 flow rate. To explain this effect, we examined the effect of Cl2 flow rate on Cl radical concentration by optical emission spectroscopy (OES). The Cl emission intensity depended on Cl2 flow rate and the substrate area. We introduced a simple model of our ECR-RIBE reactor and explained the observed dependence of emission intensity of Cl and Ga. We also explained the flow rate dependence of etching rate in terms of the effect of etching products. We obtained some rate constants of etching reactions according to our model. Our study revealed that the macroscopic phenomena in the reactor, such as the change in gas residence time, should affect the etching performances at a micron level.