High−Performance 4H−SiC UV p−i−n Photodiode: Numerical Simulations and Experimental Results

In this work, the optical response of a high−performance 4H−SiC−based p−i−n ultraviolet (UV) photodiode was studied by means of an ad hoc numerical model. The spectral responsivity and the corresponding external photodiode quantum efficiency were calculated under different reverse biases, up to 60 V, and in the wavelength range from λ = 190 to 400 nm. The responsivity peak is R = 0.168 A/W at λ = 292 nm at 0 V and improves as bias increases, reaching R = 0.212 A/W at 60 V and λ = 298 nm. The external quantum efficiency is about 71% and 88%. The good quality of the simulation setup was confirmed by comparison with experimental measurements performed on a p−i−n device fabricated starting from a commercial 4H−SiC wafer. The developed numerical model, together with the material electrical and optical parameters used in our simulations, can be therefore explored for the design of more complex 4H−SiC−based solid−state electronic and optoelectronic devices.