Effects of rapid thermal processing on the current gain and emitterresistance of polysilicon emitter bipolar transistors

Results of measurements of base current and emitter resistance of polysilicon emitter transistors subjected to different rapid thermal anneal processes of the interfacial layer and different emitter drive-in times are presented. It is shown that a rapid thermal anneal for temperatures on the order of 1050°C leads to devices in which the base current is essentially independent of the emitter drive-in time. The emitter resistance obtained in devices given this interface anneal is considerably lower than that in devices without the anneal, and hence the values obtained are compatible with the requirements for realizing submicrometer bipolar circuits