Patent ID: 7816212

Claim:
A method of high voltage operation of a field effect transistor, comprising the steps of: providing a field effect transistor that includes a substrate, a semiconductor channel formation region disposed in a surface of the substrate, a source region and a drain region which are spaced apart from each other with the semiconductor channel formation region disposed between the source region and the drain region, a gate insulating film region disposed on the semiconductor channel formation region, a resistive gate region disposed on the gate insulating film region, a source side electrode disposed on a source region side of the resistive gate region, and a drain side electrode disposed on a drain region side of the resistive gate region; supplying a signal electric potential to the source side electrode of the field effect transistor; and supplying to the drain side electrode of the field effect transistor, from a bias circuit, a bias electric potential an absolute value of which is equal to or larger than that of a specified electric potential and which changes according to an increase or decrease in a drain electric potential.