High Breakdown Voltage (−201) $\beta $ -Ga2O3 Schottky Rectifiers

<inline-formula> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula>-Ga₂O₃ Schottky barrier diodes were fabricated in a vertical geometry structure consisting of Ni/Au rectifying contacts without edge termination on Si-doped epitaxial layers (<inline-formula> <tex-math notation="LaTeX">$10~\mu \text{m}$ </tex-math></inline-formula>, <inline-formula> <tex-math notation="LaTeX">$\text{n}\sim 4\times 10^{15}$ </tex-math></inline-formula> cm<inline-formula> <tex-math notation="LaTeX">$^{-3})$ </tex-math></inline-formula> on Sn-doped bulk Ga₂O₃ substrates with full-area Ti/Au back Ohmic contacts. The reverse breakdown voltage, <inline-formula> <tex-math notation="LaTeX">${V} _ \text {BR}$ </tex-math></inline-formula>, was a function of rectifying contact area, ranging from 1600 V at <inline-formula> <tex-math notation="LaTeX">$3.1\times 10^{-6}$ </tex-math></inline-formula> cm² (20-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> diameter) to ~250 V at <inline-formula> <tex-math notation="LaTeX">$2.2{\times }10^{-3}$ </tex-math></inline-formula> cm<inline-formula> <tex-math notation="LaTeX">$^{-2}$ </tex-math></inline-formula> (0.53-mm diameter). The current density near breakdown was not strongly dependent on contact circumference but did scale with contact area, indicating that the bulk current contribution was dominant. The lowest ON-state resistance, <inline-formula> <tex-math notation="LaTeX">${R} _\text {on}$ </tex-math></inline-formula>, was 1.6 <inline-formula> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula> cm² for the largest diode and 25 <inline-formula> <tex-math notation="LaTeX">$\text{m}\Omega \cdot $ </tex-math></inline-formula>cm² for the 1600-V rectifier, leading to a Baliga figure-of-merit (<inline-formula> <tex-math notation="LaTeX">${V} _\text {BR}^{2}/{R} _\text {on})$ </tex-math></inline-formula> for the latter of approximately 102.4 MW<inline-formula> <tex-math notation="LaTeX">$\cdot $ </tex-math></inline-formula>cm<inline-formula> <tex-math notation="LaTeX">$^{-2}$ </tex-math></inline-formula>. The ON-OFF ratio was measured at a forward voltage of 1.3 V and ranged from <inline-formula> <tex-math notation="LaTeX">$3\times 10^{7}$ </tex-math></inline-formula> to <inline-formula> <tex-math notation="LaTeX">$2.5\times 10^{6}$ </tex-math></inline-formula> for reverse biases from −5 to −40 V and showed only a small dependence on temperature in the range from 25 °C to 100 °C.