RF-MBE法によるInN薄膜の成長と評価

概要

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We have grown InN layers on sapphire (0001) substrates by radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE) using solid metal sources. Surface under growth process and resultant grown layers were characterized by RHEED, X-ray diffraction (XRD) and Hall effect measurement. Both crystal quality and surface flatness were strongly influenced by N-plasma condition, V/III ratio and buffer layer. It is found that troublesome poor adhesion of grown InN to sapphire substrate is drastically improved by using GaN buffer layer. Using GaN buffer, higher quality of InN layer as compared with that directly grown on the substrate can be obtained, although the electron mobility is reduced. Electron accumulation at the surface or InN/substrate interface is suggested by Hall effect measurement. Influence of thermal annealing in N_2, H_2 or O_2 ambient on electrical properties are investigated. Annealing in O_2 led to considerable increase of carrier density while appreciable change was not observed for N_2 annealing.
北海道工業大学の論文
2007-03-26