Lattice defect in selective epitaxial silicon and laterally overgrown regions on SiO2

Abstract The nature of the lattice defects in selective epitaxial (001) silicon in SiO 2 windows and in laterally overgrown regions on SiO 2 films were characterized using a transmission electron microscope. Stacking faults, the dominant defects in the windows with near {110} sidewalls, were eliminated in the films grown at temperatures lower than 850°C. Twinning, which was frequently observed in 〈110〉 laterally overgrown regions, was also suppressed by lowering the growth temperature, but occurred even at a growth temperature of 800°C. The generation of defects is discussed from the viewpoint of the stability of the Si/SiO 2 interface. Twin formation in laterally overgrown regions at lower growth temperatures is considered to be the result of the growth direction change from vertical to lateral. The difference in defect nature, between SFs in vertically grown regions and twins in laterally overgrown regions, is explained by the defect structure at the initial stage of generation. Films overgrown on SiO 2 along the 〈100〉 direction exhibit few defects in the temperature range of 800 to 950°C; however, dislocations and small voids are present in the region where two overgrowth fronts coalesce irrespective of the growth temperature. Typical dislocations are of screw-type, showing that they are not caused by stress relaxation.