Solid particle erosion — a statistical method for evaluation of strength properties of semiconducting materials

Abstract

The mechanical strength of brittle single-crystal materials like silicon and GaAs is to a large extent governed by their surface conditions. It is known that material removal by solid particle erosion from such materials is controlled by brittle fracture. Because of its inherent statistics, solid particle erosion yields stable and highly reproducible results with very little scatter. The erosion rate is therefore suggested as an appropriate and simple statistical measure of the susceptibility of brittle materials to surface damage in the micron range. The erosion rate of GaAs is found to be one order of magnitude higher than that of silicon and also differences in crystallographic orientations are easily detected by erosion rate measurements. The room temperature microfracture properties of silicon are found to depend neither on doping nor on the impurity content difference between CZ and FZ crystals. Scanning electron microscopy and transmission electron microscopy studies show that median and cone-type cracking must be included in erosion models for brittle materials. A simple erosion model including non-lateral spalling is presented and is shown to agree well with the experimental results and empirical power law relationships.