Oxygen precipitation and stackinghyphen;fault formation in dislocationhyphen;free silicon

摘要

The kinetics of the growth of Frank interstitial stackinghyphen;fault loops formed as a result of oxygen precipitation at high temperatures in bulk dislocationhyphen;free silicon have been measured over a temperature range 1000ndash;1200thinsp;deg;C. From TEM observations at early and later stages of stackinghyphen;fault formation, it is concluded that the fault can be nucleated at a precipitate particle (assumed to be SiO2) by either interstitial collapse or by a dislocation reaction involving a perfect dislocation dissociating to form a Shockley and Frank partial. Once nucleated, the fault grows by (1) oxygen diffusing to the central precipitate and (2) interstitials, formed to accommodate the large volume change accompanying precipitation, migrating to the stacking fault causing it to grow. A detailed model of the growth of a precipitate and its related fault involving several steps in series has been worked out in the Appendix. The assumptions underlying this derivation have been treated in the Appendix and the preceding paper. The theory predicts at3/4growth law for stacking faults which is observed experimentally over the temperature range investigated. The theory also predicts that the temperature dependence of the growth of stacking faults has an activation energy which is threehyphen;fourths of that for selfhyphen;diffusion, sim;3.8 eV for the most recent measurements.