Growth parameters on the defects formation in a grown silicon crystal

Abstract

The growth of macroscopically dislocation-free Czochralski silicon crystals, various defects such as D defects and microdefects causing oxidation-induced stacking faults can form. The effects of growth parameters such as pulling speed or cooling rate of the crystal on the formation of these defects is examined. From an experiment on the continuous cooling of a silicon crystal from 1400 °C, it is found that there is an intermediate cooling rate range in which the nucleation of OISFs is enhanced. The impact of the presence of OISFs on the electrical properties of the silicon crystal is examined with a minority lifetime mapper, and the resistivity is measured with a four-point probe. A higher pulling speed of the crystal from the melt results in a higher density of particles on the polished silicon wafers. This implies that many of the particles present on the polished silicon wafers are related to solidification of the silicon crystal. Slower pulling from the melt followed by controlled cooling thereafter is suggested as a means of lowering these grown-in defects in Czochralski silicon crystals. © 1998 Kluwer Academic Publishers