THIN FILM FIELD EFFECT TRANSISTOR

PURPOSE:To cut off the path of a leakage current on the surface of a protective insulating film, by forming an oxide film or a nitride film covering the surface of a source electrode or a drain electrode. CONSTITUTION:A gate electrode 2 is formed on a substrate 1 by using a photo etching method. A gate insulating film 3, a semiconductor layer 4 forming a channel, and an etching stopper 5 are continuously formed. An ohmic contact layer 6 is formed by etching an insulating film as the etching stopper 5. A picture element transparent electrode 7 and a source.drain electrode 8 are formed and patterned in desired shapes. An anode oxide film 10 is formed on the surface of the source-drain electrode 8. A protective insulating film 9 is formed by a plasma CVD method, and the insulating film on the picture element electrode 7 is etched and eliminated. Thereby the surface of the source- drain electrode 8 is not exposed, and the generation of a leakage current can be prevented.