Three-mesa p-Pi-n structured III-nitride semiconductor avalanche photodetector and preparation method thereof

The invention relates to the technical field of detectors, in particular to a three-mesa p-Pi-n structured III-nitride semiconductor avalanche photodetector and a preparation method of the three-mesa p-Pi-n structured III-nitride semiconductor avalanche photodetector. The three-mesa p-Pi-n structured III-nitride semiconductor avalanche photodetector comprises a substrate, a buffer layer, an n-type doping nitride ohmic electrode contact layer, a Pi-type nitride active layer, a p-type doping nitride layer, a p-type heavy-doping nitride ohmic contact layer, n-type ohmic contact electrodes and a p-type ohmic contact electrode, wherein the buffer layer, the n-type doping nitride ohmic electrode contact layer, the Pi-type nitride active layer, the p-type doping nitride layer and the p-type heavy-doping nitride ohmic contact layer are sequentially grown on the substrate through epitaxial growth methods such as a molecular beam epitaxial method or an organometallic chemical vapor deposition epitaxial method; the n-type ohmic contact electrodes are manufactured on the n-type layer, and the p-type ohmic contact electrode is manufactured on the p-type layer. The three-mesa p-Pi-n structured III-nitride semiconductor avalanche photodetector can solve the problems that a traditional p-i-n structured device leaks a large number of currents and the edge of the traditional p-i-n structured device can be broken through easily in advance; moreover, a three-mesa structure conducts double-suppression protection on edge electric fields of a strong electric field region and a weak electric field region of a p-Pi-n structured device, so that the edge electric field is effectively prevented from being broken through in advance.