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Proceedings Paper

Electron beam induced current study of minority carrier diffusion length in homoepitaxial GaN (Conference Presentation)
Author(s): A. Alec Talin; Kimberlee C. Collins; Andrew M. Armstrong; Andrew A. Allerman; François Léonard

Paper Abstract

GaN is a promising material for a range of high power, high frequency, and high temperature device applications. The wide bandgap of GaN leads to high breakdown voltages and low switching losses. Recently, large HVPE grown GaN substrates have become available for homoepitaxial growth leading to ~103 reduction in dislocation density compared to similarly grown heteroepitaxial films. Device performance, however, is ultimately limited by the transport properties of minority carriers. Measured values for minority carrier diffusion lengths and lifetimes in GaN vary widely1-3, and a recent report suggests flaws in the commonly adopted electron beam induced current (EBIC) method in the planar-collection geometry.1 Here we report on EBIC measurements performed on ~8 micrometer thick GaN grown by MOCVD on 2 inch GaN substrates with a n-type dopant density of ~5×1016 cm-3. We determine the carrier diffusion length using both the conventional EBIC method by varying the electron beam-to-contact lateral distance as well as by varying the electron beam penetration depth and find the extracted values differ by ~10×, with the latter technique yielding the lower diffusion length. We rationalize these results in light of other materials characteristics including Raman and photoluminescence. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Paper Details

Date Published: 3 November 2016
PDF: 1 pages
Proc. SPIE 9924, Low-Dimensional Materials and Devices 2016, 99240B (3 November 2016); doi: 10.1117/12.2239742
Show Author Affiliations
A. Alec Talin, Sandia National Labs. (United States)
Kimberlee C. Collins, Sandia National Labs. (United States)
Andrew M. Armstrong, Sandia National Labs. (United States)
Andrew A. Allerman, Sandia National Labs. (United States)
François Léonard, Sandia National Labs. (United States)

Published in SPIE Proceedings Vol. 9924:
Low-Dimensional Materials and Devices 2016
Nobuhiko P. Kobayashi; A. Alec Talin; M. Saif Islam; Albert V. Davydov, Editor(s)

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