Low-dislocation-density silicon-on-insulator material produced by sequential oxygen implantation and low-temperature annealing

Lattice strain and defect formation in oxygen-implanted silicon (SIMOX) were investigated by high-resolution x-ray diffraction and transmission electron microscopy. At doses of 1×1017 and 3×1017 cm−2 a high density of vacancy-type defects formed in a uniaxially compressed layer at the surface of the as-implanted wafer. Annealing at 900 °C for 0.5 h reduced this negative strain as the defects coarsened into observable cavities. The development of cavities upon annealing was used in a sequential-implantation and low-temperature-annealing process to produce low-threading dislocation density SIMOX. This new process offers several advantages over other methods of producing low-dislocation-density material.