JPS6447081A - Semiconductor photodetector - Google Patents

Abstract

PURPOSE:To effectively prevent any breakdown from occurring by raising breakdown voltage in a guard ring part by providing the guard ring in a first semiconductor part of a curvature of a PN junction plane of a second semiconductor region formed in the first semiconductor layer, the second semiconductor layer having a higher carrier concentration than that of the first semiconductor layer and having the same conductivity type as that of the latter. CONSTITUTION:An n<+>-InP multiplying layer 5 is provided by an epitaxial growth process in an epitaxially grown n--InP window layer 6. And, a p<+> layer and a pn junction plane 14 are provided more deeply than a photodetector part 7 which is brought into contact with the multiplying layer. And further, a p- guard ring part 8 is provided in the window layer 6, which part includes a larger part of the curvature of the pn junction plane 14. The larger part of the curvature of the pn junction plane is more deeply formed than the pn junction plane 14 which is brought into contact with the avalanche multiplying layer 5 for reducing the curvature. For this, the larger part of the curvature of the pn junction plane and the guard ring 8 having a slanting type junction including the former are provided in the window layer of a low carrier concentration.