Semiconductor device with a gate having a bulbous area and a flattened area underneath the bulbous area and method for manufacturing the same

摘要

A semiconductor device with a gate having a bulbous area and a flattened area underneath the bulbous area is presented. The semiconductor device includes a semiconductor substrate, an isolation layer, a gate insulation layer, and gates. The semiconductor substrate has recess parts that have first grooves which have bulbous-shaped profiles and second vertically flattened profile grooves which extend downward from the first grooves. The gates are formed in the recess parts in which the gate insulation layer is double layered in the bulbous profile areas and is single layered in the flattened profile areas.

主权项

1. A method for manufacturing a semiconductor device, comprising the steps of:
forming an isolation layer in a semiconductor substrate to delimit an active region; defining first grooves, which have a bulbous-shaped profile, in gate forming areas of the active region; forming a first insulation layer on surfaces of the first grooves; defining recess parts by etching portions of the first insulation layer which constitute bottoms of the first grooves and portions of the active region which are placed under the bottoms of the first grooves and thereby defining second grooves; etching the isolation layer to expose front and rear surfaces of the gate forming areas in which the recess parts are defined; forming a second insulation layer on surfaces of the recess parts, including the first insulation layer, to form a gate insulation layer comprising the first insulation layer and the second insulation layer; and forming gates in the recess parts, in which the gate insulation layer is formed, on the exposed front and rear surfaces of the gate forming areas.