Impact of substrate temperature on the incorporation of carbon-related defects and mechanism for semi-insulating behavior in GaN grown by molecular beam epitaxy

Journal Article · Mon Feb 20 04:00:00 EST 2006 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.2179375· OSTI ID:20778690

Armstrong, A; Poblenz, C; Green, D S; Mishra, U K; Speck, J S; Ringel, S A ^[1]

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1. Department of Electrical and Computer Engineering, Ohio State University, Columbus, Ohio 43210 (United States)

The electrical conductivity and deep level spectrum of GaN grown by molecular beam epitaxy and codoped with carbon and silicon were investigated for substrate temperatures T{sub s} of 650 and 720 deg. C as a function relative carbon and silicon doping levels. With sufficiently high carbon doping, semi-insulating behavior was observed for films grown at both temperatures, and growth at T{sub s}=720 deg. C enhanced the carbon compensation ratio. Similar carbon-related band gap states were observed via deep level optical spectroscopy for films grown at both substrate temperatures. Due to the semi-insulating nature of the films, a lighted capacitance-voltage technique was required to determine individual deep level concentrations. Carbon-related band gap states underwent substantial redistribution between deep level and shallow acceptor configurations with change in T{sub s}. In light of a T{sub s} dependence for the preferential site of carbon incorporation, a model of semi-insulating behavior in terms of carbon impurity state incorporation mediated by substrate temperature is proposed.

• OSTI ID: 20778690
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 8 Vol. 88; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CAPACITANCE
CARBON
CRYSTAL DEFECTS
CRYSTAL GROWTH
DEEP LEVEL TRANSIENT SPECTROSCOPY
ELECTRIC CONDUCTIVITY
ELECTRIC POTENTIAL
ENERGY GAP
FILMS
GALLIUM NITRIDES
IMPURITIES
LAYERS
MOLECULAR BEAM EPITAXY
SEMICONDUCTOR MATERIALS
SILICON
SUBSTRATES