Self-Aligned SiGe-Base Heterojunction Bipolar Transistor by Selective Epitaxy Emitter Window (SEEW) Technology

Joachim N. Burghartz, James H. Comfort, Gary L. Patton, Bernard Meyerson, Jack Y.C. Sun, Johannes M.C. Stork, Siegfried R. Mader, Carol L. Stanis, Gerald J. Scilla, Barry J. Ginsberg

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24 Scopus citations


The first reported self-aligned heterojunction bipolar transistor (HBT) in silicon technology is presented. A SiGe epitaxial base is integrated in a structure which uses in-situ doped epitaxial lateral overgrowth for the formation of the emitter window and the extrinsic base contact. Nearly ideal I- V characteristics have been achieved for a base width of 60 nm with an intrinsic base resistance of 4.6 kΩ/∓ and for emitter widths down to 0.4 μm. A dc collector current enhancement factor of 3.1 was obtained relative to a Si homojunction transistor with a 1.25 times higher intrinsic base resistance. The breakdown voltage BVCBO is identical for both Si and SiGe devices, even though the collector-base (C-B) depletion region is partly overlapped with the reduced-bandgap SiGe strained layer. The lower BVCE0, measured for the SiGe-base transistor, is due to the higher current gain. Based on these results the fabrication of high-speed bipolar circuits that take advantage of SiGe-base bandgap engineering seems possible using selective epitaxy emitter window (SEEW) technology.

Original languageEnglish
Pages (from-to)288-290
Number of pages3
JournalIEEE Electron Device Letters
Issue number7
StatePublished - Jul 1990

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