METHOD FOR MANUFACTURING THIN FILM TRANSISTOR

摘要

PURPOSE: A method for manufacturing a thin film transistor is to provide a thermal oxide layer having a high uniformity by stacking a doped amorphous silicon thin film and an undoped amorphous silicon thin film to thereby form a gate electrode. CONSTITUTION: An insulating layer(100) is formed on a semiconductor substrate. A gate conductive layer(110) is formed on the insulating layer. The gate conductive layer includes a doped amorphous silicon thin film(111) and an undoped amorphous silicon thin film(112). A gate insulating layer(120) is formed on the gate conductive layer. A channel polysilicon layer(130) is formed on the gate insulating layer. Impurity ions are selectively implanted on the channel polysilicon layer to thereby form a source/drain region(150). The doped amorphous silicon thin film is formed through an LP-CVD(low pressure chemical vapor deposition) process using an Si source gas, such as SiH4 and Si2H6, and PH3 source gas.