SIMS, RBS, ion channelling, and TEM studies of the low energy SIMOX structures

Abstract

Abstract Device grade single crystal 〈100〉 silicon wafers have been implanted with 70 keV oxygen ions over a dose range from 3.3 × 1017 to 10 × 1017/cm2 at 680 °C and subsequently annealed at 1320 °C for 2 or 6 h. Secondary ion mass spectrometry (SIMS), Rutherford backscattering (RBS), ion channelling, and planar and cross sectional transmission electron microscopy (TEM) have been used to follow the evolution of the as-implanted and annealed structures. It has been shown that the mechanisms responsible for the buried oxide layer formation at 70 keV appear to be similar to those at 200 keV, with the as-implanted microstructure playing an important role in determining the final structure of the annealed wafer. As the dose increases the values of Xmin in the as-implanted and annealed samples increases as does the threading dislocation density in the silicon overlayer of the annealed wafers. Increasing anneal time (from 2 to 6 h) improves the two interfaces (Si/SiO2 and SiO2 /Si), but has little effect on the dislocation density and the distribution of silicon islands.