Investigation of Ga₂O₃/diamond heterostructure solar-blind avalanche photodiode via TCAD simulation

A Ga₂O₃/diamond separate absorption and multiplication avalanche photodiode (SAM-APD) with mesa structure has been proposed and simulated. The simulation is based on an optimized Ga₂O₃/diamond heterostructure TCAD physical model, which is revised by repeated comparison with the experimental data from the literature. Since both Ga₂O₃ and diamond are ultra-wide bandgap semiconductor materials, the Ga₂O₃/diamond SAM-APD shows good solar-blind detection ability, and the corresponding cutoff wavelength is about 263 nm. The doping distribution and the electric field distribution of the SAM-APD are discussed, and the simulation results show that the gain of the designed device can reach 5 × 10⁴ and the peak responsivity can reach a value as high as 78 A/W.