Growth of $\alpha-Ga_2O_3$ on $Al_2O_3$ by conventional molecular-beam epitaxy and metal-oxide-catalyzed epitaxy

TL;DR

This paper demonstrates improved growth of $ ext{Ga}_2 ext{O}_3$ on $ ext{Al}_2 ext{O}_3$ using both conventional MBE and In-mediated MOCATAXY, achieving higher growth rates and better film quality.

Contribution

It introduces a growth-rate diagram for $ ext{Ga}_2 ext{O}_3$ and shows how MOCATAXY enhances growth rate, window, and film quality compared to conventional methods.

Findings

In-mediated catalysis increases growth rate and reduces mosaic spread.

Growth rates over 0.2 μm/hr achieved with MOCATAXY.

Faceting observed and analyzed via electron microscopy.

Abstract

We report the growth of $\alpha-Ga_2O_3$ on $m$-plane $Al_2O_3$ by conventional plasma-assisted molecular-beam epitaxy (MBE) and In-mediated metal-oxide-catalyzed epitaxy (MOCATAXY). We report a growth-rate-diagram for $\alpha-Ga_2O_3$ (10-10), and observe (i) a growth rate increase, (ii) an expanded growth window, and (iii) reduced out-of-lane mosaic spread when MOCATAXY is employed for the growth of $\alpha-Ga_2O_3$. Through the use of In-mediated catalysis, growth rates over $0.2\,\mu\text{m}\,\text{hr}^{-1}$ and rocking curves with full width at half maxima of $\Delta\omega \approx 0.45^{\circ}$ are achieved. Faceting is observed along the $\alpha-Ga_2O_3$ film surface and is explored through scanning transmission electron microscopy.