FORMATION MECHANISMS OF DISLOCATION AND SI ISLAND IN LOW-ENERGY SIMOX

Changes in the microstructure and oxygen depth profile during high-temperature annealing have been measured using TEM, RBS and AES in the silicon-on-insulator film fabrication process by separation by implanted oxygen (SIMOX) with 25-keV oxygen ions. Densities of threading dislocation in the top Si layer and Si islands in the SiO2 layer were drastically reduced at high implantation temperature (740-degrees-C). These were closely connected with the structure and oxygen depth profile in the as-implanted Si. It was also found that the threading dislocations originate from SiOx precipitates distributed in the top Si layer, and that Si/SiOx layered fine structure which appeared in an early stage of the annealing generates the Si islands after annealing.