Electronic near-surface defect states of bare and metal covered n-GaN films observed by cathodoluminescence spectroscopy

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Journal of Electronic Materials

DOI:https://doi.org/10.1007/s11664-999-0032-z· OSTI ID:345076

Young, A P; Schaefer, J; Brillson, L J ^[1]; Yang, Y; Xu, S H; Cruguel, H; Lapeyre, G J ^[2]; Johnson, M A.L.; Schetzina, J F ^[3]

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1. Ohio State Univ., Columbus, OH (United States)
2. Montana State Univ., Bozeman, MT (United States). Physics Dept.
3. North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics

The electronic states at metal contacts to GaN are of significant concern for a wide range of microelectronic and optoelectronic device applications. Depth-dependent low energy cathodoluminescence spectroscopy (CLS) has been used to investigate the near-surface optical properties of n-type GaN epilayers grown under various growth conditions. Both bare and reacted-Mg/n-GaN and Al/n-GaN (annealed to 1,000 C) surfaces were investigated. The authors find enhanced emission at {approximately} 1.4, 1.6, and 2.2 eV from states within the n-type GaN bandgap near the interface of the reacted Mg with the semiconductor, which correlates with previous measurements of Schottky barrier formation on the same specimens. No clear evidence for p-type doping at the reacted interfacial layer is apparent. For Al on n-type GaN, CLS emission is dominated before and after metallization by yellow emission, which correlates only weakly with the Fermi level stabilization energy. Instead, the authors observe emission above the GAN band edge emission at 3.85 eV, due either to deep level emission from AlN or to the formation of the alloy Al{sub x}Ga{sub 1{minus}x}N (x {approx} 0.2) in the reacted near-surface region.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG02-97ER45666
• OSTI ID: 345076
• Report Number(s): CONF-9806176--
• Journal Information: Journal of Electronic Materials, Journal Name: Journal of Electronic Materials Journal Issue: 3 Vol. 28; ISSN JECMA5; ISSN 0361-5235
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALUMINIUM
ELECTRIC CONTACTS
EXPERIMENTAL DATA
GALLIUM NITRIDES
INTERFACES
MAGNESIUM
OPTICAL PROPERTIES
SEMICONDUCTOR DEVICES
SPECTROSCOPY
THIN FILMS