METHOD FOR MANUFACTURING THIN FILM TRANSISTOR

摘要

PURPOSE: A fabrication method of a thin film transistor is provided to enhance an on/off current ratio by filling an etched portion with a nitride after forming a gate by undercut etching. CONSTITUTION: A conductive layer is formed on a thick oxide layer(2) of a substrate. A gate is formed by undercut etching the conductive layer. After forming a nitride layer on an entire surface, a sidewall of the nitride layer is formed on a side of the gate by etching back thereof. A gate insulating layer is formed on the resultant structure. A polysilicon layer(5) for a body is formed on the gate insulting layer. A source(6) and a drain(7) are formed by implanting selectively an ion on the polysilicon layer for the body and by recrystallizing process.