講演情報
[16p-W9_324-4]Epitaxial Growth of Gallium Oxide (1):
High-Density Oxygen Radical Source (HD-ORS) for MBE and PVD
〇(P)Michael Mo1, Arun Kumar Dhasiyan1, Nikolay Britun1, Naohiro Shimizu1, Osamu Oda1,2, Masaru Hori1 (1.Nagoya Univ., CLPS, 2.NU-Rei, Inc.)
キーワード：
thin film growth、gallium oxide、molecular beam epitaxy
β-Ga2O3 is a promising candidate for future power device applications, but the major challenge to overcome the homoepitaxy of β-Ga2O3 by Molecular Beam Epitaxy (MBE) is the low growth rate due to the two-step growth kinetics: the intermediate formation of the gallium suboxide (Ga2O) in the first step and the further oxidation of Ga2O to Ga2O3 in the second step. Since the Ga2O has a significantly higher vapor pressure than that of Ga, its desorption limits the growth rate due to two factors: (1) metal-rich conditions, which provide insufficient O-flux to oxidize formed suboxide, and (2) high substrate temperatures at which the thermally activated desorption of Ga2O outperforms its oxidation even under O-rich growth conditions. We consider a more efficient oxygen plasma source to be crucial for overcoming the growth-rate limitations arising from the intermediate formation of volatile Ga2O. A high-density plasma source can promote the further oxidation of Ga2O into solid β-Ga2O3. With this motivation, we have developed a High-Density Oxygen Radical Source (HD-ORS) that employs a mixture of ozone and oxygen to generate atomic oxygen for MBE and Physical Vapor Deposition (PVD) systems.