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Crystal orientations of β‐Ga 2 O 3 thin films formed on m ‐plane and r ‐plane sapphire substrates
Author(s) -
Nakagomi Shinji,
Kaneko Satoru,
Kokubun Yoshihiro
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201451456
Subject(s) - sapphire , crystal (programming language) , plane (geometry) , materials science , crystallography , substrate (aquarium) , gallium , optics , chemistry , geometry , physics , geology , mathematics , laser , oceanography , computer science , metallurgy , programming language
We have used X‐ray pole figure analyses to study crystal orientations of β‐Ga 2 O 3 thin films formed on (100) m ‐plane or (102) r ‐plane sapphire substrates prepared by gallium evaporation in oxygen plasma. The (−201) plane of β‐Ga 2 O 3 on the (100) m ‐plane was inclined to be along two (110) a ‐planes. Crystals of (−201)‐oriented β‐Ga 2 O 3 exhibit six‐fold symmetry in which a β‐Ga 2 O 3 crystal is rotated every 60° from [001] for each a ‐plane. In all, twelve kinds of β‐Ga 2 O 3 crystals formed on m ‐plane sapphire substrate. Similarly, the (−201) plane of β‐Ga 2 O 3 on the (102) r ‐plane was inclined to be along to two (113) n ‐plane. Crystals of (−201)‐oriented β‐Ga 2 O 3 exhibit three‐fold symmetry with a β‐Ga 2 O 3 crystal rotated every 120° from the opposite direction of projection of the c ‐axis of each n ‐plane. In all, six kinds of β‐Ga 2 O 3 crystals formed on the r ‐plane sapphire substrate. These observations can be explained by comparing oxygen atomic arrangements on the β‐Ga 2 O 3 (−201) plane with those on the sapphire (110) a ‐plane and (113) n ‐plane.