Ion beam synthesis of thin buried layers of SiO(2) in silicon.

New experiments are reported which explore the possibility of using ion implantation to form thin (2000Angstroms) buried layers of stoichiometric SiO(2) in single crystal silicon. Silicon (100) wafers have been implanted with 0(+) ions within the dose range 0.1 x 10(18) to 1.5 x 10(18)0(+) cm(-2) at a particle energy of 200 keV and a substrate temperature of 500C. Both (100) channelled and non-channelled implants have been carried out. Samples were subsequently annealed at temperatures of up to 1405C, which causes the oxygen to segregate at the peak of the implanted oxygen distribution. The high dose samples (>0.6 x 10(18)0(+) cm(-2)) have a continuous buried oxide layer whose thickness scales with the implanted dose. In samples implanted with 0.1 x 10(18) 0 cm(-2), discrete strain-free polyhedral precipitates, 500Angstroms to 1600Angstroms in diameter, grow within the single crystal silicon matrix by a mechanism which is qualitatively similar to oxygen precipitation in C- Z bulk silicon.