JPS6448471A - Semiconductor photodetector and the manufacture thereof - Google Patents

Abstract

PURPOSE:To produce a photodetector which can be formed easily and has a high photoelectric conversion efficiency, by forming an InP layer, so-called a window layer on a P type InGaAs surface layer, the band gap of said former being wider than that of said latter. CONSTITUTION:An InGaAs P-N junction with a large effective area is formed, and at the same time an InP window layer 5 is formed of which the band gap is wide compared with that of InGaAs layer 3, 4, by employing both processes of the InGaAs layers being so grown as to fill up the groove of a substrate using a liquid phase epitaxial growth technique, and the InGaAs layers 3, 4 being melted back by an InP fused liquid. A light receiving surface 10 is so illuminated by light beams that a large number of pairs of electron and hole are generated in the InGaAs P-N junction. Now, because the P type InP layer 5 has a wide band gap compared with that of the InGaAs layers, the P type InP layer 5 so acts as to effectively introduce the incident light into the P-N junction part without absorbing therein the incident light. Moreover, both the window and the P-N junction are formed in a V-shape, which produces a large junction area. As a result, a photodetector can be produced at a low cost which is of good photoelectric conversion efficiency.