Adsorption-controlled growth of Ga2O3 by suboxide molecular-beam epitaxy.

This paper introduces a growth method—suboxide molecular-beam epitaxy (S-MBE)—which enables a drastic enhancement in the growth rates of Ga₂O₃ and related materials to over 1 μ m h⁻¹ in an adsorption-controlled regime, combined with excellent crystallinity. Using a Ga + Ga₂O₃ mixture with an oxygen mole fraction of x(O) = 0.4 as an MBE source, we overcome kinetic limits that had previously hampered the adsorption-controlled growth of Ga₂O₃ by MBE. We present growth rates up to 1.6 μ m h⁻¹ and 1.5 μ m h⁻¹ for Ga₂O₃/Al₂O₃ and Ga₂O₃/Ga₂O₃ structures, respectively, with very high crystalline quality at unparalleled low growth temperature for this level of perfection. We combine thermodynamic knowledge of how to create molecular beams of targeted suboxides with a kinetic model developed for the S-MBE of III–VI compounds to identify appropriate growth conditions. Using S-MBE, we demonstrate the growth of phase-pure, smooth, and high-purity homoepitaxial Ga₂O₃ films that are thicker than 4.5 μ m. With the high growth rate of S-MBE, we anticipate a significant improvement to vertical Ga₂O₃-based devices. We describe and demonstrate how this growth method can be applied to a wide range of oxides. With respect to growth rates and crystalline quality, S-MBE rivals leading synthesis methods currently used for the production of Ga₂O₃-based devices. [ABSTRACT FROM AUTHOR]