Doping of β-Ga${}_2$O${}_3$ layers by Zn using halide vapor-phase epitaxy process

Development of ultrawide bandgap semiconductor β-Ga${}_2$O${}_3$ is important considering its great potential for high-power high-voltage electronic applications. Halide vapor-phase epitaxy is used to produce Zn-doped β-Ga${}_2$O${}_3$ layers on sapphire (0001). Zn doping concentrations is estimated to be in the range between 6 × 10${}^{18}$ and 2.5 × 10${}^{20}$ cm${}^{-3}$. As a precursor for Zn acceptor dopant, ZnCl${}_2$ 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 β-Ga${}_2$O${}_3$ 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. (© 2021 The Authors. physica status solidi (a) applications and materials science published by Wiley‐VCH GmbH)