Oxidation of silicon implanted with high-dose aluminum

Si (100) wafers were implanted with Al at 500 C to high doses at multi-energies and were oxidized in 1 atm flowing oxygen at 1,000--1,200 C. The morphology, structure, and oxidation behavior of the implanted and oxidized Si were studied using optical microscopy, atomic force microscopy, and cross-sectional transmission electron microscopy in conjunction with selected area electron diffraction and energy dispersive x-ray analysis. Large Al precipitates were formed and embedded near the surface region of the implanted Si. The oxidation rate of the Al-implanted Si wafers was lower than that of virgin Si. The unique morphology of the implanted Si results from rapid Al diffusion and segregation promoted by hot implantation. The reduction of the oxidation rate of Si by Al implantation is attributed to the preferential oxidation of Al and formation of a continuous diffusion barrier of Al2O3