Reduction of UHF power transistor distortion with a nonuniform collector doping profile

W.D. Van Noort, L.C.N. De Vreede, H.F.F. Jos, L.K. Nanver, J.W. Slotboom

Research output: Contribution to journalArticleAcademicpeer-review

15 Citations (Scopus)


The linearity of a class-A, bipolar UHF power transistor is investigated. The device is intended for transmission of signals with multiple (TV) channels. Mixing between the various channels must be suppressed, which makes linearity an important parameter. This paper presents a novel approach, where process technology is specifically optimized to minimize distortion. It is shown that particularly the nonlinear collector-base capacitance strongly affects the linearity of this type of device. With a modified collector-base doping profile, the capacitance is manipulated. A nonuniform profile is introduced that significantly reduces third-order intermodulation. The profile consists of an arsenic doped spike that is grown epitaxially into the (otherwise) lightly doped collector. This reduces the bias dependence of Ccb and improves the tradeoff between linearity and breakdown or ruggedness. The reduction in third-order intermodulation is demonstrated both experimentally and by mixed-level MDS/MAIDS simulations.

Original languageEnglish
Pages (from-to)1399-1406
Number of pages8
JournalIEEE journal of solid-state circuits
Issue number9
Publication statusPublished - Sept 2001
Externally publishedYes


  • Bipolar transistor
  • Collector-base capacitance
  • Epitaxy
  • Intermodulation distortion


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