Study of the microstructure of low energy (70 keV) oxygen implanted silicon

Abstract

Device grade (100) single crystal silicon wafers have been implanted with 70 keV oxygen ions over a dose range from 3.3×1017 /cm2 to 10×1017/cm2 at a temperature of 680 °C. The wafers were subsequently annealed at 1320 °C for 6 h. Transmission electron microscopy and ion channeling studies show that both the as-implanted microstructure and the damage distribution play an important role in determining the final microstructure of the annealed wafer. As the dose increases so does both the values of χmin for both as-implanted and annealed wafers, and the threading dislocation density in the silicon overlayer of the annealed wafers. For the wafer implanted with 70 keV oxygen ions at the lowest dose (3.3×1017/cm2), the threading dislocation density in the silicon overlayer after annealing was less than 105/cm2.