Silicon-on-sapphire with microsecond carrier lifetimes

Abstract

The lifetime in silicon films epitaxially grown on sapphire is usually in the nanosecond range. We have recently succeeded in growing such silicon‐on‐sapphire (SOS) layers with lifetimes of several microseconds. These films were grown at 1025 °C by first forming an n⁺ film on sapphire followed by a moderately doped n layer. The heavily phosphorus‐doped n⁺ layer appears to act as an effective getter and is the key to the high lifetime values.