Crystal surface defects and oxygen gettering in thermally oxidized bonded SOI wafers

This work investigates the role of interstitial oxygen content in the start ing Czochralski bonding wafers, and the effects of buried layered implants and thermal processing on the formation of crystalline defects in the surfa ce of bonded silicon on insulator (SOI) material. We found that unimplanted SOI material originating from Si with high oxygen levels (>7.0 X 10(17)/cm (3)), were populated with heavy oxygen precipitation and related crystal de fects, and were also characterized by low minority carrier lifetime values. However, a dramatic improvement was observed in the behavior of SOI with l ow oxygen levels (6 X 10(17)/cm(3)), where the development of oxygen precip itation in the SOI layer was inhibited. Incorporation of a buried As ion im planted layer in high oxygen level SOI increased the lifetime of the materi al and suppressed the formation of oxygen precipitates through an oxygen ge ttering effect. The gettering efficiency of the buried defect layer was fou nd to be related to the dose of the As ion implantation, the annealing temp erature, and type of starting silicon material. A dose of (1-5) X 10(15)cm( -2) was sufficient for effective gettering. (C) 2001 The Electrochemical So ciety. All rights reserved.