Comprehensive study of emitter-ledge thickness of InGaP/GaAs HBTs

Ssu I. Fu, Shiou Ying Cheng, Tzu Pin Chen, Po Hsien Lai, Yan Ying Tsai, Ching Wen Hung, Chih Hung Yen, Wen Chau Liu

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7 Citations (Scopus)


A comprehensive study of emitter-ledge thickness of InGaP/GaAs heterojunction bipolar transistors (HBTs) has been undertaken. It is shown that the recombination rate and electron densities are drastically increased near the exposed base surface between the base contact and the emitter ledge. In contrast, the corresponding hole densities are decreased. If the emitter ledge is too thick, current will flow through the undepleted ledge, which increases the emitter-size effect. In contrast, if the emitter ledge is too thin, it may not effectively passivate the surface. Therefore, the thickness of the emitter ledge is a crucial issue and should be carefully considered. It is shown that, from simulated and experimental results, the optimum emitter-ledge thickness of InGaP/GaAs HBT is 100-200 Å.

Original languageEnglish
Pages (from-to)2689-2695
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number11
Publication statusPublished - 2006 Nov 1

All Science Journal Classification (ASJC) codes

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

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