Method of producing insulated-gate field effect transistor

A method of producing a FET with an inverse-T gate on a semiconductor substrate, comprising the steps of:

• doping first conductivity type impurities on a first density into a device region delimited on one surface of a semiconductor substrate;
• forming a gate insulating layer, a first conductive layer, and a masking layer which can be selectively etched with respect to said gate insulating layer on said semiconductor substrate wherein said first conductivity type impurities have been doped, said first conductive layer being formed or amorphous silicon;
• forming an opening in said masking layer to expose said first conductive layer in predetermined region delimited in said device region;
• forming a side wall layer comprising an insulating material on a side of said masking layer exposed in said opening;
• doping second conductivity type impurities having a second density capable of compensating for said first density of said first conductivity type impurities into said semiconductor substrate by using said masking layer as a mask, said masking layer having said side wall layer in said opening;
• forming a second conductive layer for selectively filling said opening therewith and in contact with said first conductive layer on said semiconductor substrate into which said second conductivity type impurities have been doped;
• removing at least said masking layer from said semiconductor substrate on which said second conductive layer has been formed;
• and
• selectively removing said first conductive layer, exposed by removing said masking layer, by using at lest said second conductive layer as a mask,
• whereby said inverse-T gate electrode is formed having a leg comprising said second conductive layer and a top comprising said first conductive layer.