Method for manufacturing gate terminal

Abstract

A method for manufacturing a gate terminal comprising the steps of providing a substrate, then forming and patterning an oxide layer to form a gate region. Next, a gate oxide layer and a crystalline silicon layer are formed in the gate region. This is followed by depositing a tungsten layer in the gate region, and then polishing the tungsten layer to form a final tungsten layer functioning as the gate electrode. Finally, the oxide layer is removed. The method of this invention is able to control the dimensions of the gate terminal produced. Moreover, the formation of a thin crystalline silicon layer over the gate oxide layer helps to increase the bonding strength with the metallic layer, and that the gate electrode can be formed at a lower processing temperature. Therefore, the gate so formed has a higher quality and the processing of the semiconductor is much easier. Furthermore, the silicon nitride layer can serve as an etching stop layer during the etching operation of the oxide layer. Consequently, over-exposing the upper trench corner locations of a shallow trench isolation structure can be prevented, thereby avoiding current leakage problems.