Carbon-doped base GaAs/AlGaAs heterojunction bipolar transistor grown by metalorganic chemical vapor deposition using carbon tetrachloride as a dopant source

B. T. Cunningham, G. E. Stillman, G. S. Jackson

Research output: Contribution to journalArticle

Abstract

Carbon tetrachloride (CCl4) has been used as a carbon doping source for the base region of a GaAs/AlGaAs Npn heterojunction bipolar transistor (HBT) grown by low-pressure metalorganic chemical vapor deposition (MOCVD). Transistors were fabricated and characterized for dc current gain, emitter-base junction ideality factor, base contact resistance, and external base resistance. Microwave characterization by S-parameter measurement was performed to determine the common emitter current gain and maximum available gain as a function of frequency. Transistors with the base contact area self-aligned to a 3×10 μm emitter finger had a dc current gain as high as 50, an emitter-base junction ideality factor of n=1.2, and a current gain cutoff frequency of ft=26 GHz. Transistors of equal emitter area without self-alignment exhibited dc current gain as high as 86, n=1.2, and ft=20 GHz. A base contact resistance of Rc=2. 85×10-6 Ω cm2 and an external base sheet resistance of Rs=533.4 Ω/D'Alembertian were measured. These preliminary results indicate that carbon doping from CCl4 may be an attractive substitute for Zn or Mg in GaAs/AlGaAs HBT structures grown by MOCVD.

Original languageEnglish (US)
Pages (from-to)361-363
Number of pages3
JournalApplied Physics Letters
Volume56
Issue number4
DOIs
StatePublished - Dec 1 1990

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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