Effect of rapid thermal processing on high temperature oxygen precipitation behaviour inCzochralski silicon wafer

Abstract

The effect of rapid thermal processing (RTP) on the oxygen precipitation occurring at1050 °C in a Czochralski (CZ) silicon wafer has been investigated. It has been proved thatthe RTP-induced vacancies only enhance the early stage oxygen precipitation at1050 °C in terms of the precipitation rate. Furthermore, it is somewhat unexpected that after a lengthy1050 °C anneal the oxygen precipitates generated in the CZ silicon wafer with prior RTP treatmenthad considerably lower density and larger sizes in comparison with those generated in theCZ silicon wafer without prior RTP treatment. The reason for this is that the prior RTPtreatment will dissolve some of the grown-in oxygen precipitates, thus making the RTP-treatedwafer possess fewer nuclei contributing to oxygen precipitation in the subsequent1050 °C anneal. Moreover, the numbers of resulting precipitated oxygen atoms due to a lengthy1050 °C anneal were nearly the same in the CZ silicon wafers with and without prior RTPtreatment. Additionally, it has been illustrated that the high temperature RTP hassuperior capability to dissolve the existing oxygen precipitates. It is worthwhile to point outthat, when addressing the effect of RTP on the oxygen precipitation behaviour duringthe subsequent anneal, two functions arising from the RTP treatment, that is,the injection of vacancies into the silicon wafer and the dissolution of grown-inoxygen precipitates existing in the silicon wafer, should be taken into account.