AlGaN/SiC Heterojunction Ultraviolet Photodiodes

We report on improvement in the deep ultraviolet (DUV) photoresponse of SiC based detectors through the development of n- AlxGa1-xN / i-p SiC heterojunction photodiodes. Fabricated photodiodes have high external quantum efficiency (EQE), greater than 60%, over a wide spectral range from 215-255 nm that is ~10x enhancement in performance over comparable homogenous SiC photodiodes at the shortest wavelength. This is attributed to photogeneration of carriers within the SiC depletion region by DUV illumination of the diode through the n- AlxGa1-xN “window”, as compared to a typical homogenous SiC n-i-p structure where the carriers are photogenerated in the n-type neutral region, resulting in more efficient collection of holes through drift