Unintentional doping effect in Si-doped MOCVD β-Ga2O3 films: Shallow donor states

High-quality β-Ga2O3 films were epitaxially grown by using metalorganic chemical vapor deposition (MOCVD) with different donor concentrations, and their shallow states investigated the temperature-dependent Hall measurement secondary ion mass spectroscopy (SIMS) analysis. Two levels ionization energies of ∼36 ∼140 meV extracted. It is found that unintentional doping (UID) effects in MOCVD contribute substantially to both these two levels: first level may come not only from silicon but also substitution carbon for Ga sites, second probably comes doubly charged defects related H doping. By analyzing relationship between growth conditions states, combined density functional theory calculations, it reducing oxygen partial pressure during might be a feasible way reduce UID effect. This work paves precise control carrier Si-doped films.