Field-effect semiconductor device having open drain output

Abstract

Abstract PURPOSE:To protect a gate insulation film by providing a junction diode on a substrate provided with MOSFET, connecting the diode with a source and a drain and thereby preventing a generation of a strong electric field between the gate and the drain. CONSTITUTION:On the N-type substrate 26 are provided a P channel FET 27 comprising the source 23, the drain 24 and a gate electrode 22 and an avalanche diode 28 comprising a P-type anode 29 and an N<+> cathode 30. The cathode 30 of the diode 28 is connected with the source 23 and the connection terminal 31 of the anode 29 with the drain 24, respectively, and an output terminal is provided in a wiring 36 for connecting the drain. In this device, the diode 28 is short-circuited when voltage of V1 or more or of V1-Vs or less is given to the output terminal 32, given that supply voltage given to a terminal 37 is V1 and that the yield voltage of the diode 28 is Vs. Since the occurrence of the high electric field in the region of the drain 24 can be prevented in this way, the breakdown of the gate film 25, as well as the fluctuation of threshold-value voltage owing to injection of charge, can be prevented.

Inventors

• 👤 Tatsuo Mimura
• 👤 Koichi Onizuka

Bibliographic Details