Effect of Growth Parameters on the Residual Stress and Dislocation Density of Czochralski-Grown Silicon Crystals

Abstract

This paper discusses the effects of pull rate and rotation rate on the dislocation density and residual stress distributions in Czochralski-grown silicon crystals. A photoelastic technique was used to study the residual stress. It was found that a pull rate of 7. 62 cm/h and a rotation rate of 12 rpm yielded a nearly ideal radial stress pattern and a relatively low and constant distribution of dislocations. In general, when the dislocation density increases from the center to the periphery, and the crystal has not undergone extensive plastic flow, an optical pattern indicative of a radial stress distribution is observed. Conversely, crystals which exhibit dislocation distributions that decrease toward the periphery and have undergone plastic flow show an optical pattern which indicates a departure from a radial stress.