Rapid thermal annealing of in situ phosphorus-doped polysilicon emitters

Abstract

Rapid thermal annealing of in situ phosphorus-doped polysilicon emitter transistors in the temperature range 850–1000 °C greatly reduces the emitter resistance RE at the cost of a slight increase in hole back injection, seen as a decrease in emitter Gummel number GE. Annealing at 1000 °C for 5 s gives low emitter resistance (RE ≈ 100 Ω μm2) while maintaining good suppression of back injection (GE ≥ 1014 scm−4). Annealing at temperatures below 1000 °C fails to reduce RE sufficiently for use in high-speed devices.