Patent ID: 7375016

Claim:
A method for fabricating a semiconductor device, comprising the steps of: (a) forming a device isolation film defining an active region by performing a STI process on a pad insulating film formed on a semiconductor substrate; (b) forming a polysilicon layer on an entire surface of the semiconductor device; (c) defining an island-type recess region passing across the active region, and then etching the polysilicon layer, the pad insulating film and the device isolation film by a predetermined thickness in the island-type recess region to form a recess exposing both sidewalls of the active region, wherein a width of the island-type recess region is smaller than a width of a gate region in a first direction and a length of the island-type recess region is larger than a width of the active region in a second direction wherein the first direction is defined in the active region and the second direction is defined in the gate region, the first direction being substantially perpendicular to the second direction; (d) etching the semiconductor substrate within the recess using the remaining polysilicon layer as an etching mask to form a recess gate region, wherein the polysilicon layer and the semiconductor substrate are simultaneously etched; (e) removing the pad insulating film by a predetermined thickness, and then forming a gate oxide film on the active region; (f) forming a lower gate conductive layer filling up the recess gate region on the entire surface of the semiconductor device and sequentially forming a upper gate conductive layer and a hard mask layer on the lower gate conductive layer; and (g) selectively etching the hard mask layer, the upper gate conductive layer and the lower gate conductive layer using a gate mask to form a gate structure.