A new method of producing a buried oxide is proposed. It involves implanting
a silicon wafer with helium rather than oxygen ions and then subjecting it
to high- temperature oxidation. The voids formed by helium ion implantation
and subsequent annealing enhance the diffusion of oxygen atoms into the
silicon. The oxygen atoms cause thermal oxide to grow at the void/silicon
interface and transform the voids into buried oxide precipitates. Auger
electron spectroscopy revealed that the total number of oxygen atoms in the
precipitates was 9.3 × 1016 cm−2 and that the peak
value of oxygen atom concentration in the wafer was approximately 25%.