Electrical detection of defects in SIMOX buried oxides: pipes and precipitates

Summary form only given. Two defect types have been identified in the buried oxide of low dose SIMOX: conductive silicon paths through the buried oxide (pipes) and silicon precipitates in the buried oxide. Both types are caused by the same general mechanism: the tendency of the Si-SiO/sub 2/ system at high temperature to separate into regions of Si and SiO/sub 2/, rather than forming SiO/sub x/. Below an oxygen dose of /spl sim/4/spl times/10/sup 17/ cm/sup -2/, the buried oxide is not continuous, and as the dose is lowered, the implanted region becomes a layer of SiO/sub 2/ precipitates. Above the dose of /spl sim/4/spl times/10/sup 17/ cm/sup -2/, the buried oxide is continuous, but Si precipitates /spl sim/50 nm thick are present in the oxide. This paper demonstrates techniques for the electrical detection of precipitates and pipes in low dose SIMOX buried oxides.