Evaluation of surface defects on SIMOX and their influences on device characteristics

Surface defects on two types HD SIMOX wafers that made of CZ wafers and epi taxial wafers as starting materials were examined for their shape and densi ty. It was found that surface defects on HD SIMOX wafers were mainly classi fied into two categories. One was "pit-type" and another was "undulation-ty pe". It is considered that the former defects are originated from grown-in defects, such as COPs, and the latter defects are caused by SIMOX process, such as oxygen ion implantation and/or SIMOX anneal. Furthermore, deformati ons of surface defects by sacrificed oxidization for SOI thinning and the i nfluences on GOI and BOX quality were investigated. It was found that some undulation-type defects that lost the SOI layers during SOI thinning degrad ed GOI and that some other undulation-type defects that lost aboriginally t he SOI layers degraded both the GOI and BOX quality. (C) 2000 Elsevier Scie nce B.V. All rights reserved.