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1 August 1990 AlGaAs/GaAs pnp HBTs with high fmax and ft
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Proceedings Volume 1288, High-Speed Electronics and Device Scaling; (1990)
Event: Advances in Semiconductors and Superconductors: Physics Toward Devices Applications, 1990, San Diego, CA, United States
AlGaAs/GaAs Pnp HBTs have the potential for high frequency performance approaching that of Npn HBTs. To achieve this performance, it is necessary to dope the base as heavily n-type as possible. This heavy base doping results in large degeneracy in the base, which reduces the heterobarrier to reverse injection of electrons from the base into the emitter. High A1 content in the emitter is desirable to maintain good injection efficiency. Incorporating a gradient in the base doping can introduce fields to sweep injected holes across the neutral base region, which reduces base transport time. DC and RF characteristics of Pnp HBTs with 40% and 75% Al in the emitter will be presented. ft of 17 GHz and fmax of 39 GHz has been achieved in 2 ?m x 11 ?m HBTs fabricated using a self-aligned ohmic contact process. Further improvement in performance should be possible.
© (1990) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Gerard J. Sullivan, M. F. Chang, Neng Haung Sheng, Robert J. Anderson, Nan Lei Wang, Keh-Chung Wang, J. Aiden Higgins, and Peter M. Asbeck "AlGaAs/GaAs pnp HBTs with high fmax and ft", Proc. SPIE 1288, High-Speed Electronics and Device Scaling, (1 August 1990);

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