Growth parameters on the defects formation in a grown silicon crystal

The growth of macroscopically dislocation-free Czochralski silicon crystals , various defects such as D defects and microdefects causing oxidation-indu ced stacking faults can form. The effects of growth parameters such as pull ing 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 crys tal from 1400 degrees 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 ex amined with a minority lifetime mapper, and the resistivity is measured wit h a four-point probe. A higher pulling speed of the crystal from the melt r esults in a higher density of particles on the polished silicon wafers. Thi s 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. (C) 199 8 Kluwer Academic Publishers.