Epitaxial growth of GaN on lattice-matched hafnium substrates

Conference · Fri Nov 01 04:00:00 EST 1996

OSTI ID:394930

Beresford, R; Stevens, K S; Briant, C; Bai, R; Paine, D C ^[1]

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1. Brown Univ., Providence, RI (United States). Div. of Engineering

A method of producing epitaxial GaN on single-crystal Hf has been developed. The metal substrate is formed by a strain-anneal process yielding macroscopic (5-mm) grain sizes, followed by polishing, chemical etching, and Ar ion sputtering at elevated temperature in ultrahigh vacuum. The growth is conducted by plasma-assisted molecular beam epitaxy using an initial passivation layer deposited at low temperature and subsequent growth at 700 C. The resulting films are in registry with the hcp substrate lattice as observed by reflection high-energy electron diffraction during growth and verified by plan-view transmission electron microscopy. High-resolution x-ray rocking curve linewidths of the GaN and Hf [10{bar 1}2] peaks are as narrow as 900 and 180 arc seconds, respectively. The [0002] peak separation confirms the approximately 2.7% mismatch in the c axis spacing. Initial photoluminescence observations at 20 K of a (donor-bound exciton) peak at 3.467 eV are consistent with the assumption of a nearly strain-free film resulting from the exact basal-plane lattice match and close thermal coefficient match between GaN and Hf.

• OSTI ID: 394930
• Report Number(s): CONF-951155--; ISBN 1-55899-298-7
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
CHEMICAL REACTIONS
ELECTRON DIFFRACTION
ENERGY BEAM DEPOSITION
GALLIUM NITRIDES
GRAIN ORIENTATION
GRAIN SIZE
LIGHT EMITTING DIODES
MATERIALS
MOLECULAR BEAM EPITAXY
PHOTOLUMINESCENCE
PLASMA
RECRYSTALLIZATION
SUBSTRATES
SURFACE CLEANING
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION