Improvement of buried oxide integrity in ITOX SIMOX wafers

Low-dose SIMOX wafers are very encouraging for fabrication of SOI ULSI devices because of their better crystalline quality and higher wafer production throughput compared with high-dose SIMOX wafers. However, as the buried oxide (BOX) layer becomes thinner, it is generally more difficult to fulfill severe requirements concerning the BOX integrity. This is because the breakdown of the thin BOX is caused by Si pipes and Si islands, which are left in the buried layer during SIMOX manufacturing. In this paper we present the results of electrical evaluation of the buried oxide layers synthesized with doses from 2.7 to 3.5 X 10¹⁷ cm^-2