High-speed InGaP/GaAs HBT's with a strained InxGa1-xAs base

D. A. Ahmari, M. T. Fresina, Q. J. Hartmann, D. W. Barlage, P. J. Mares, M. Feng, G. E. Stillman

Research output: Contribution to journalArticlepeer-review


A self-aligned InGaP/GaAs heterojunction bipolar transistor with a compositionally graded InxGa1-xAs base has been demonstrated with fT = 83 GHz and fmax = 197 GHz. To our knowledge, these results are the highest reported for both parameters in InGaP/GaAs HBT's. The graded base, which improves electron transport through the base, results in a dc current gain and a cutoff frequency which are 100% and 20% higher, respectively, than that achieved by an identical device with a nongraded base. The high fmax results from a heavily doped base, self-aligned base contacts, and a self-aligned collector etch. These results demonstrate the applicability of InGaP/GaAs HBT's in high-speed microwave applications.

Original languageEnglish (US)
Pages (from-to)226-228
Number of pages3
JournalIEEE Electron Device Letters
Issue number5
StatePublished - May 1996

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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