Method of making field effect transistor

Claim 1

A production method of an asymmetric gate field effect transistor comprising: producing a gate electrode on a substrate and depositing an insulating film on said substrate and completely covering said gate electrode; depositing a photoresist film on said insulating film that completely covers said gate electrode; producing a photoresist pattern from said photoresist film, said photoresist pattern having an opening spaced from said gate electrode exposing part of said insulating film spaced from said gate electrode; selectively removing said insulating film only at the opening using said photoresist pattern as a mask leaving a remaining part of said insulating film in place; removing said photoresist pattern; implanting ions into said substrate to form source and drain regions using the remaining part of said insulating film as a mask at said drain region and forming said source region where said insulating film has been removed; removing the remaining part of said insulating film; and forming source and drain electrodes on said source and drain regions, respectively.