Patent 7282768 was granted and assigned to Seiko Instruments on October, 2007 by the United States Patent and Trademark Office.
A high-reliable depletion-type MOS field-effect transistor as a process monitor is provided. A diode formed in polycrystalline silicon and a diode formed in a semiconductor substrate form a bi-directional diode. The bi-directional diode connects a gate electrode with the semiconductor substrate in the depletion-type MOS field-effect transistor through metal wirings.