Inductive load driving circuit

Abstract

The objective of this invention is to provide a photodiode which has high sensitivity even to light with a wavelength in the blue region while maintaining the high-frequency characterstics. The n type second semiconductor layer () containing an n type electroconductive impurity at a low concentration is formed directly or via an intrinsic semiconductor layer () on the p type first semiconductor layer (). The third semiconductor layer () containing an n type electroconductive impurity at a medium concentration is formed shallower than said second semiconductor layer () in its main plane. The fourth semiconductor layer () containing an n type electroconductive impurity at a high concentration is formed shallower than said third semiconductor layer () in the main plane of the third semiconductor layer (). The metal-containing electroconductive layer () is formed on said fourth semiconductor layer () in the same layout as the fourth semiconductor layer (), with the third semiconductor layer () and the fourth semiconductor layer () being separated by the second semiconductor layer () in at least one cross section.