METHOD FOR FORMING GATE ELECTRODE SPACER

摘要

PURPOSE: A forming method of a gate electrode spacer is provided to prevent an excess etch of an isolation region and a not open of a semiconductor device. CONSTITUTION: A method for forming a gate spacer(18a,18b) of a gate electrode(14) formed on a semiconductor substrate(10) comprises the steps of: forming a first insulating layer on the semiconductor substrate and the gate electrode; forming a second insulating layer on the first insulating layer; forming the gate spacer on both side walls of the gate electrode by etching the second insulating layer by using the first insulating layer as an etch stop layer(16); and etching the first insulating layer until a surface of the semiconductor substrate is exposed. The first insulating layer is formed of Si3N4, and the second insulating layer is formed of oxide. The first and the second insulating layer have an etching selectivity ratio of 50:1.