Determination of minority carrier diffusion lengths in the denuded zones of silicon wafers by surface photovoltage measurements

Abstract

Modern VLSI devices are fabricated in the top few microns of silicon wafers known as the oxygen denuded zone. In this zone, intrinsic gettering is used to improve the quality and purity of the silicon crystal. In this paper, we show, for the first time, that a modified surface photovoltage technique that we have developed can be used to measure the minority carrier diffusion lengths in the denuded zones of silicon wafers. This will provide the IC industry with a simple, direct and non-destructive method of monitoring the effectiveness of the intrinsic gettering process during VLSI fabrication.