Study of plasma etching of silicon carbide

Abstract

Etching is a very crucial process in the fabrication of SiC microelectronic devices. Due to its exceptional chemical inertness, plasma etching is the only practical means of etching SiC. With more stringent requirements placed on the etch rate, etching profiles, surface quality for advanced SiC devices, it is of great importance to understand the mechanisms and behaviors of SiC plasma etching, including the physical damages involved and its consequences on the electrical characteristics of the devices. In this work, the etching behaviors of n type bulk 4H-SiC was studied using RIE and ECR etching processes, using halogen based chemicals, with/without added oxygen. The etch rate, surface roughness and contamination have been measured and analyzed. The etching of SiC based on the ECR plasma technique has been modeled using an artificial neural network based on an improved training algorithm. The modeling results were studied and physical interpretations were given. The plasma etching induced electrical damage was studied using Schottky barrier diodes as test devices. The objective of this project is to develop an optimum plasma etching process for the fabrication of SiC power devices, with precise etching control and minimum induced damage.