A new intrinsic gettering technique using microdefects in Czochralski silicon crystal: A new double preannealing technique

A new intrinsic gettering technique using microdefects in Czochralski-grown silicon wafers is proposed where a new double preannealing technique is applied to the wafer before the conventional silicon process. In the first step, high temperature (∼1000 °C), nonoxygen ambient annealing is carried out in order to diffuse dissolved oxygen from near the wafer surface. In the second step, extremely low-temperature (∼650 °C) annealing is added to introduce a high density of microdefects in the inner part of the wafer. This produces a wafer having both a nearly perfect denuded zone near the surface and a gettering site region in its bulk, regardless of the original quality of the wafer. This technique has proved to be effective in eliminating ion-implanation oxidation-induced stacking faults.