Low surface recombination velocity and contact resistance usingp+/pcarbon‐doped GaAs structures
作者:
T. J. de Lyon,
J. A. Kash,
S. Tiwari,
J. M. Woodall,
D. Yan,
F. H. Pollak,
期刊:
Applied Physics Letters
(AIP Available online 1990)
卷期:
Volume 56,
issue 24
页码: 2442-2444
ISSN:0003-6951
年代: 1990
DOI:10.1063/1.102903
出版商: AIP
数据来源: AIP
摘要:
A reduction of the GaAs surface recombination velocity due to a heavily carbon‐doped GaAs overlayer is reported. Metalorganic molecular beam epitaxy using trimethylgallium, triethylgallium, and elemental arsenic sources has been used to grow an epitaxial structure consisting of 1000 nm ofp=1×1017cm−3capped with 10 nm ofp=1×1020cm−3GaAs. Time‐resolved photoluminescence (PL) and PL excitation spectroscopy showed thisp+/pstructure to have a 3.2 ns carrier lifetime and strong band‐edge PL emission, whose intensity was nearly constant over an excitation photon energy range of 1.5–3.3 eV. The same wafer with thep+cap etched off exhibited a much shorter carrier lifetime and PL intensity that decreased exponentially with increasing photon energy, which is indicative of carrier losses to surface recombination. The specific contact resistivity of nonalloyed ohmic contacts to these heavily doped layers was observed to be in the mid 10−7&OHgr; cm2range, independent of measurement temperature from 77 to 340 K, suggesting a tunneling contact due to the narrow surface depletion layer.
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