METHOD FOR MANUFACTURING DUAL GATE ELECTRODE

摘要

PURPOSE: A method for fabricating a dual gate electrode is to reduce a mask process by implanting an impurity ion into a gate electrode formed by a polysilicon layer or an amorphous silicon layer. CONSTITUTION: An isolation insulating layer(13) is formed in a semiconductor substrate(10). A p-well(11) and an n-well(12) are formed at the semiconductor substrate. A gate insulating layer is grown on the entire surface of the semiconductor substrate. A polysilicon layer is formed on the gate insulating layer. A gate electrode is formed by etching the polysilicon layer, using a gate electrode mask as an etching mask. An n-LDD(lightly doped drain) region is formed by implanting an n-impurity ion having a low concentration into the entire surface of the semiconductor substrate. A p-LDD region is formed by implanting a p-impurity ion having a low concentration into the entire surface of the semiconductor substrate. An insulating layer spacer is formed on the sidewall of the gate electrode. An n+ gate electrode and an n+ source/drain region(18a) are formed by implanting an n+ impurity ion having a high concentration on both sides of the insulating layer spacer and the gate electrode.