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Analysis of Leakage Currents in AlGaN/GaN Current Aperture Vertical Electron Transistors (CAVETs)

Published online by Cambridge University Press:  01 February 2011

Ilan Ben-Yaacov ,
Yee-Kwang Seck ,
Steven P. DenBaars ,
Evelyn L. Hu  and
Umesh K. Mishra
Ilan Ben-Yaacov
Affiliation:
ECE Department, University of California Santa Barbara, CA 93106-9560, U.S.A.
Yee-Kwang Seck
Affiliation:
ECE Department, University of California Santa Barbara, CA 93106-9560, U.S.A.
Steven P. DenBaars
Affiliation:
ECE Department, University of California Santa Barbara, CA 93106-9560, U.S.A.
Evelyn L. Hu
Affiliation:
ECE Department, University of California Santa Barbara, CA 93106-9560, U.S.A.
Umesh K. Mishra
Affiliation:
ECE Department, University of California Santa Barbara, CA 93106-9560, U.S.A.
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Abstract

A complete analysis of leakage currents in AlGaN/GaN Current Aperture Vertical Electron Transistors (CAVETs) with regrown aperture and source regions was carried out. The total observed leakage current was found to be a combination of both gate leakage and source leakage. Two paths for source leakage have been identified; electrons passing directly through the insulating layer to the drain region as well as electrons traveling through the aperture but underneath the 2DEG at the AlGaN/GaN interface. Source leakage through the insulating layer resulted from pits formed at the onset of regrowth, as the sample was heated to growth temperature, and was successfully eliminated by optimizing regrowth conditions. Source leakage underneath the 2DEG occurred when the unintentionally doped (UID) GaN layer above the insulating layer was not fully depleted and could be eliminated by reducing the thickness of the UID GaN layer. Gate leakage has been attributed to the enhanced incorporation of n-type impurities inside as well as above the aperture region during regrowth, resulting in a narrowing ofthegateSchottkybarrier.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 764: Symposium C – New Applications for Wide-Bandgap Semiconductors , 2003 , C4.8
Copyright
Copyright © Materials Research Society 2003

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