AL PROCESSING FOR IMPURITY GETTERING IN SILICON

摘要

A method is provided for gettering impurities from silicon wafers and devices to improve the quality of the material and the device performance. The wafer or the device is coated on the back-side with a layer of aluminum and is illuminated form the other side with light having a significant portion of energy in the IR region. This process leads to formation of a Si-Al melt on the backside, at temperature below 550° C. Dissolved impurities in the Si diffuse toward the Al melt and are trapped there. At higher illuminations and concomitant higher temperatures, the Al interface serves as a source of point defect injection. This mode of processing causes dissolution of precipitated impurities at greatly reduced temperatures and in short periods of time.