Reduction of saucer pit microdefects in epitaxial silicon wafer by intrinsic gettering

The reduction of microdefects in epitaxial silicon wafers is achieved by a two-step annealing consisting of dry O2 and wet O2 heat treatments based on intrinsic gettering. The gettering mechanism is investigated by means of infrared absorption, an etching procedure, and transmission electron microscopy. It has been found that inner defects which are correlated with the gettering action after the second annealing are classified into three groups depending on the first annealing temperatures from 700 to 1050 °C, that is, small stacking faults, cristobalites, and climbing dislocations are dominant in samples annealed at ≲800, 800∼900, and ≳900 °C, respectively. The depth of the denuded zone is also discussed.