Gettering of Metals by Voids in Silicon Devices

A new gettering process for metallic impurity in silicon is described. Voids are formed by high dose helium implants followed by thermal processes. The method takes advantage by the unsatured Si bonds present in the void surface which act as sinks for metallic impurities present in the matrix. The efficiency of this gettering process is demonstrated higher than conventional methods based on intentional crystal dislocation formation. Moreover the void characteristics allow a new gettering engineering for silicon devices.