N-type SIPOS and poly-silicon emitters

N-type SIPOS and poly-silicon emitters on silicon show potential for improved minority carrier blocking properties over conventional diffused emitters. This paper discusses experiments designed to elucidate the physical mechanisms responsible for this improvement and to optimize the process conditions. Emitters both with and without an intentionally grown chemical oxide under the SIPOS or poly-silicon film are investigated. Both poly-silicon and SIPOS emitters, in their optimized form, can achieve Joe of less than 2 × 10−14 A/cm2, an improvement of several decades over shallow diffused emitters.