Journal Article Epitaxial structure and electronic property of <i>β</i>-Ga<sub>2</sub>O<sub>3</sub> films grown on MgO (100) substrates by pulsed-laser deposition

若林, 諒  ,  Wakabayashi, Ryo  ,  吉松, 公平  ,  Yoshimatsu, Kohei  ,  服部, 真依  ,  Hattori, Mai  ,  大友, 明  ,  Ohtomo, Akira

111p.162101 , 2017-10 , AIP Publishing
Description
We investigated heteroepitaxial growth of Si-doped Ga2O3 films on MgO (100) substrates by pulsed-laser deposition as a function of growth temperature (Tg) to find a strong correlation between the structural and electronic properties. The films were found to contain cubic γ-phase and monoclinic β-phase, the latter of which indicated rotational twin domains when grown at higher Tg. The formation of the metastable γ-phase and twin-domain structure in the stable β-phase are discussed in terms of the in-plane epitaxial relationships with a square MgO lattice, while crystallinity of the β-phase degraded monotonically with decreasing Tg. The room-temperature conductivity indicated a maximum at the middle of Tg, where the β-Ga2O3 layer was relatively highly crystalline and free from the twin-domain structure. Moreover, both crystallinity and conductivity of β-Ga2O3 films on the MgO substrates were found superior to those on α-Al2O3 (0001) substrates. A ratio of the conductivity, attained to the highest quantity on each substrate, was almost three orders of magnitude.

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