MOCVD growth of (010) β-(AlxGa1-x)2O3 thin films

In this work, we systematically investigate the effects of growth parameters on the structural and surface morphological properties of beta-(AlxGa1-x)(2)O-3 thin films grown on (010) beta-Ga2O3 substrates via metalorganic chemical vapor deposition (MOCVD). By varying [TMAl]/[TEGa + TMAl] molar flow rate ratio, growth temperature and chamber pressure, (i) the structural and physical properties of beta-(AlxGa1-x)(2)O-3 films including Al incorporations, growth rates, strain properties, rocking curve full width at half maximum, and (ii) the surface morphological properties are investigated. Higher [TMAl]/[TEGa + TMAl] molar flow ratio leads to higher Al incorporation in beta-(AlxGa1-x)(2)O-3 films. Higher growth temperature promotes lower growth rates with substantial surface roughening, although the Al incorporation remains similar for a given [TMAl]/[TEGa + TMAl] molar flow ratio. In addition, increasing chamber pressure leads to lower growth rates and lower Al incorporation in the AlGaO films. This study reveals that the MOCVD growth window for (010) beta-(AlxGa1-x)(2)O-3 films becomes narrower as the Al composition increases.