Laser surface processing for stress and damage mitigation in SIC

Abstract

This paper provides an update on experiments in the use of pulsed laser ablation (10 ps to 120 ns) as a technique for mitigation of surface stress and damage in silicon carbide is provided. SiC is of interest for a wide range of applications due to its thermal, optical, and electrical properties as well as its dimensional stability. However, concerns about handling damage and unpredictable breakage may limit its use. Machining, grinding and even polishing of this brittle material leaves a damaged surface layer of depth approximately proportional to the size of the abrasive used to finish it. This damage layer is a potential source of crack initiation, and its mitigation is desirable. The damage layer is accompanied by compressive stress. Measurements of the changes in this stress can be used to track improvements in the surface. The Twyman method is used to demonstrate and quantify the degree to which laser ablation can be used to remove the damage layer in variously prepared samples of SiC, and potentially lead to improved reliability of this material and other brittle materials.This paper provides an update on experiments in the use of pulsed laser ablation (10 ps to 120 ns) as a technique for mitigation of surface stress and damage in silicon carbide is provided. SiC is of interest for a wide range of applications due to its thermal, optical, and electrical properties as well as its dimensional stability. However, concerns about handling damage and unpredictable breakage may limit its use. Machining, grinding and even polishing of this brittle material leaves a damaged surface layer of depth approximately proportional to the size of the abrasive used to finish it. This damage layer is a potential source of crack initiation, and its mitigation is desirable. The damage layer is accompanied by compressive stress. Measurements of the changes in this stress can be used to track improvements in the surface. The Twyman method is used to demonstrate and quantify the degree to which laser ablation can be used to remove the damage layer in variously prepared samples of SiC, and potential...