Process and device performance of a high-speed double poly-Si bipolar technology using borosenic-poly process with coupling-base implant

摘要

Use of boron and arsenic diffusions through an emitter polysilicon film (borosenic-poly emitter-base process) produces a transistor base width of less than 100nm with an emitter junction depth of 50 nm and an emitter-to-base reverse leakage current of approximately 70 pA. The borosenic-poly process resolves both the channeling and shadowing effects of a sidewall-oxided spacer during the base boron implantation. The process also minimizes crystal defects generated during the emitter and base implantations. The coupling-base boron implant significantly improves a wide variation in the emitter-to-collector periphery punchthrough voltage without degrading the emitter-to-base breakdown voltage current gain, cutoff frequency, or ECL gate delay time. A deep trench isolation with 4- mu m depth and 1.2- mu m width reduces the collector-to-substrate capacitance to 9 fF, while maintaining a transistor-to-transistor isolation voltage of greater than 25 V. The application of self-aligned titanium silicide technology to form polysilicon resistors without holes and to reduce the sheet resistance of the emitter and collector polysilicon electrodes to 1 Omega /square is discussed.