JPS6464264A - Semiconductor photo detector using circular electrode - Google Patents

Abstract

PURPOSE:To enable the measurement of light incidence position displacement and incident energy, with a simple structure, by arranging a circular electrode and a center electrode, on the periphery of a resistive layer and at a center, respectively, and leading out, from each electrode, a current of electric charge generated by incidence of light, which current flows through the resistive layer. CONSTITUTION:When light enters an Si layer 2 though a substrate 5 and a transparent electrode 4, electric charge generates in the layer, in response to the energy of incident light, and a current flows to each electrode through a resistive layer 1. In the case where a resistor R is not connected, and the current is lead out directly from a center electrode, the detected current from the center electrode becomes small, as a light incidence position goes toward the periphery, and on the contrary, the current increases in a circumference electrode. In the case where the center electrode is not formed, and the current is lead out only by the circumference electrode, the circumference current does not change regardless of the change of light incidence position. If a resistor R having almost equal resistance corresponding to the radius length of the resistive layer 2 of a detector is connect to the central electrode, and the detection is performed in this state, an electrically almost equivalent state to the case where the central electrode does not exist can be obtained. As a result, the circumference current can be made constant.