Indentation hardness and modulus of the surface of a large super-polished single crystal silicon sphere

Abstract

Surface properties of single crystal silicon are of great interest to many people in research and development as well as in industry, particularly the semiconductor industry. In this paper we present and discuss the results of a series of nanoindentations as they relate to the elasticity and microhardness properties on the surface of a large single crystal silicon sphere. The sphere is 94 mm, it has a total roundness error of <213 nm P-V, and a super-polished surface <0.4 nm rms. The cubic structure of a silicon crystal displays different properties of hardness and elasticity in the different crystallographic planes. We present a study of the measurable differences in these mechanical properties as they relate to the <111> and the <100> directions. We show how these differences affect the overall shape of the sphere during the surface finishing process.