SEMICONDUCTOR PHOTODETECTOR

PURPOSE:To facilitate anode grounding and cathode grounding freely without using a submount and provide a construction in which monolithic integration with other devices is possible by a method wherein a cathode is provided on the same side of an InP insulating substrate as an anode. CONSTITUTION:An n type InP window layer 4, a light-absorbing n type InGaAs layer 3 and an n-type InP buffer layer 2 ground a light detecting region 6 are removed by etching and an n-type electrode 10 which is a cathode is formed on an n type InP layer 1a. Therefore, even if PD is mounted on a package, both the cathode 10 and anode 11 floating from the package so that one of or both of the cathode and anode can be grounded or made to float and the single PD can meet all the electrode arrangements. Moreover, as the cathode 10 and the anode 11 surrounding the light detecting region 6 are formed on the same side of an InP insulating substrate 1, the PD and a device such as an FET which has an amplifying function and a light emitting device such as an LD can be integrated on a same insulating substrate to form a monolithic integrated circuit.