Formation of denuded zone and bulk microdefects in a czochralski-grown silicon wafer by internal gettering

摘要

In this study we investigated the formation ofdenuded zone and bulk microdefects by three-step-annealing in aCzochralski grown silicon wafer. Three-step-annealing wasperfoemed in a sequence of high temperature (900~1100degC),low temperature (600~800degC) and medium temperature(850~950degC) respectively. Oxygen concentration profiles byoutdiffusion in the 1st step annealing were calculated using error-function-solutions to Fick's 2nd law. Based on these results,denuded zone width were determined after the 2nd and the 3rd stepannealing. The calculated values of denuded zone width werecorrelated well with the measured ones. The denuded zone widthwas found out to be proportional to the square root of denudationtime (the 1st step annealing time). Morphological changes of bulkmicrodefects were observed according to changes of the 3rd stepannealing time. Finally the effect of pre-oxidation on the changesof denuded zone width is also discussed.