First Demonstration of Ga2O3 Trench MOS-Type Schottky Barrier Diodes

We developed <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga₂O₃ trench MOS-type Schottky barrier diodes (MOSSBDs) for the first time. A Si-doped Ga₂O₃ layer was grown via halide vapor phase epitaxy on a single-crystal Sn-doped <inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga₂O₃ (001) substrate. The trench structure was fabricated using dry etching and photolithography. HfO₂ film was used as the dielectric film of the trench MOS structure. The specific on-resistances (<inline-formula> <tex-math notation="LaTeX">${R} _{{ \mathrm{ON},\mathsf {SP}}}$ </tex-math></inline-formula>) of the normal SBD and trench MOSSBD were about 2.3 and 2.9 <inline-formula> <tex-math notation="LaTeX">$\text{m}\Omega $ </tex-math></inline-formula>cm<inline-formula> <tex-math notation="LaTeX">$^{{\mathsf {2}}}$ </tex-math></inline-formula>, respectively. The reason the <inline-formula> <tex-math notation="LaTeX">${R} _{{ \mathrm{ON},\mathsf {SP}}}$ </tex-math></inline-formula> of MOSSBD was a little higher than that of the Schottky barrier diodes (SBD) is that the current path decrease as a result of forming the trench MOS structure. The normal SBD had a large reverse leakage current due to the large electric field at the anode metal/semiconductor interface. On the other hand, the trench MOSSBD had several orders of magnitude smaller leakage current. We, thus, demonstrated that incorporating the trench MOS structure in Ga₂O₃ is highly effective for decreasing the reverse leakage current.