Plasma-Assisted Molecular Beam Epitaxy 2

This chapter sheds light on various fundamental aspects of the O plasma-assisted molecular beam epitaxy of Ga2O3. It discusses the volatile suboxide-related growth kinetics of Ga2O3 explaining the observed growth rate behavior as function of all growth parameters. The binary growth kinetics of Ga2O3 is then compared to that of its related oxides In2O3 and SnO2. During the ternary growth of (InxGa1-x)2O3, thermodynamic aspects based on different metal-oxygen bond strengths become important, which will be shown to govern the Ga- versus In-incorporation into the (InxGa1-x)2O3 thin film. More importantly, we describe how the collaborative effect of the different growth kinetics and thermodynamics of the binary oxides can lead to a strong growth rate enhancement of Ga2O3 by metal-exchange catalysis (MEXCAT) using In2O3 or SnO2 as catalyst. A brief overview of the polymorphs of Ga2O3 stabilized by different substrates is given. The surface morphology obtained by homoepitaxy will be discussed in relation to thermodynamically induced faceting. Finally, open questions will be identified that require further research.