Ultrashallow Diffused Emitter-Base Profiles For Bipolar Device Applications Using Rapid Thermal Processing

The viability of rapid thermal processing is assessed for the fabrication of extremely shallow emitter-base profiles in bipolar devices. Junctions diffused from polysilicon using either rapid thermal processing (RTP) or conventional furnace drives are characterized using secondary ion mass spectrometry (SIMS). Results are compared to SUPREM III simulations of the diffusion process. Electrical data is compared for npn polysilicon emitter bipolar devices with emitter-base junctions fabricated using either an RTP emitter drive at 10500C or a conventional furnace drive at 9100C. Potential advantages and disadvantages of RTP are discussed including polysilicon/silicon interface control and required temperature uniformity.