We present experimental evidence that minority electron transport across a thin, quasineutral p+ GaAs region is limited by the thermal velocity of the electrons rather than by conventional diffusive transport. A set of GaAs homojunction np+n transistors with base widths of 4000, 2000, 1000, and 500 Å was fabricated and characterized. The diffusive modelpredicts that the dc collector current of the 500‐Å base width transistors should be eight times larger than the collector current of transistors with a 4000‐Å‐wide base. The experimental results, however, show only a factor of ~3.5 increase in collector current. The measured collector current versus base width characteristic agrees well with theoretical treatments of thin‐base transport. These new results present evidence of quasiballistic electron transport in p+ GaAs and have important implications for GaAs transistor design.


Copyright (1993) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Appl. Phys. Lett., Vol. 64, No. 2, 10 January 1994 and may be found at http://dx.doi.org/10.1063/1.111505. The following article has been submitted to/accepted by Applied Physics Letters. Copyright (1995) E. S. Harmon, M. R. Melloch, M. S. Lundstrom and F. Cardone. This article is distributed under a Creative Commons Attribution 3.0 Unported License.

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Appl. Phys. Lett. 64 (2), 10 January 1994



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