The Role of Dopant and Segregation Annealing in Silicon p–n Junction Gettering

The effectiveness of various procedures for heavy metal gettering in silicon p–n junctions are compared. The comparison concerns both p+–n and n+–p junctions, the substrates being p−, n−, epi p−/p+, and n−/n+. The following facts are observed: 1) boron and phosphorus are effective getter sites, while arsenic and antimony are not effective. 2) The location of these sites (in the bulk in p−/p+ substrates, on the back, in the contacts) is irrelevant for the gettering effectiveness. 3) Provided that the slice contains a sufficient amount of getter sites, the segregation anneal improves the quality of devices. 4) Oxygen precipitates and stacking faults are much less effective than phosphorus or boron heavily doped regions.