Doping of beta-Ga2O3 Layers by Zn Using Halide Vapor-Phase Epitaxy Process

Development of ultrawide bandgap semiconductor beta-Ga2O3 is important considering its great potential for high-power high-voltage electronic applications. Halide vapor-phase epitaxy is used to produce Zn-doped beta-Ga2O3 layers on sapphire (0001). Zn doping concentrations is estimated to be in the range between 6 x 10(18) and 2.5 x 10(20) cm(-3). As a precursor for Zn acceptor dopant, ZnCl2 formed by flowing of diluted Cl-2 gas over a melt of metallic Zn is used. Modeling of the growth chamber and calculations of precursor concentrations inside the growth zone is carried out to optimize process parameters. The Zn doping is not affecting the optical emission properties; however, growth under oxygen-rich conditions and formation of crystalline particles on the layer surface are factors responsible for modification of beta-Ga2O3 luminescence spectrum. It is observed that the UV band at 3.35 eV vanishes, whereas relative intensities of the blue and green bands at 2.4-2.8 eV increase.