Photocarrier lifetime and transport in silicon supersaturated with sulfur

摘要

Doping of silicon-on-insulator layers with sulfur to concentrations far above equilibrium by ion implantation and pulsed laser melting can result in large concentration gradients. Photocarriers generated in and near the impurity gradient can separate into different coplanar transport layers, leading to enhanced photocarrier lifetimes in thin silicon-on-insulator films. The depth from which holes escape the heavily doped region places a lower limit on the minority carrier mobility-lifetime product of 10-8 cm2/V for heavily sulfur doped silicon. We conclude that the cross-section for recombination through S impurities at this concentration is significantly reduced relative to isolated impurities.