Heavily Doped InP-based HBTs for New Wireless and Fiber-optic Telecommunication Applications

D. Lubyshev, Y. Wu, X.-M. Fang, T. Yurasits, W. K. Liu and A. B. Cornfeld
IQE, Inc.

IQE Inc. has developed a manufacturable MBE process for growing SHBT and DHBT structures lattice-matched to 3" and 4" diameter InP substrates. The high base doping of 4x10 19 cm -3 and small base thickness of 500 Å were chosen to support the frequency response required for new wireless and 40 Gb/s fiber-optic telecommunication products. Both beryllium and carbon were used for base doping, and produced similar DC characteristics for large-area devices. In addition to the traditional approach of lattice-matched growth on InP substrates, HBT structures were grown on GaAs substrates with metamorphic buffer layers. DC characteristics of M-HBTs was found to compare favorably with that of LM-HBTs.