Epitaxial <inline-formula> <tex-math notation="LaTeX">$\beta$ </tex-math> </inline-formula>-Ga2O3 and <inline-formula> <tex-math notation="LaTeX">$\beta$ </tex-math> </inline-formula>-(AlxGa1−x)2O3/<inline-formula> <tex-math notation="LaTeX">$\beta$ </tex-math> </inline-formula>-Ga2O3 Heterostructures Growth for Power Electronics

Abstract

We report on the growth of high quality ${\beta }$ -Ga2O3 films using metal organic chemical vapor deposition (MOCVD). Ga(DPM)3, TEGa, and TMGa metal organic precursors were used as Ga sources and oxygen for oxidation. Films grown from each Ga sources had high growth rates with up to 10 ${\mu }\text{m}$ /h achieved using TMGa. To study the quality homoepitaxial layers, MOCVD was used to grow unintentionally doped (UID) and Si doped ${\beta }$ -Ga2O3 layers with a growth rate between 0.5 and 4.0 $\mu \text{m}$ /h Epitaxial layers with XRD FWHM and RMS roughness ${n\,\,{=}\,\,8{\times }10^{19}}\,\,1$ /cm3 to ~120 cm2/Vs for ${n\,\,{=}\,\,1.6{\times }10^{17}}\,\,1$ /cm3. These values are comparable with the best literature data, despite higher growth rates. For the UID ${\beta }$ -Ga2O3 layers, Si was identified as the major impurity responsible for the free carrier concentration with strong accumulation at the film/substrate interface. The reactor was also used to grow high quality strained ${\beta }$ -(AlxGa1−x)2O3/ ${\beta }$ -Ga2O3 heterostructures and superlattices with Al content of up to 43%. The results suggest that the MOCVD enables growth of device quality ${\beta }$ -Ga2O3 and related alloys at a fast growth rate which is critical for high voltage power devices.