Method of manufacturing semiconductor device having recess gate structure with varying recess width for increased channel length

Abstract

A varying-width recess gate structure having a varying-width recess formed in a semiconductor device can sufficiently increase the channel length of the transistor having a gate formed in the varying-width recess, thereby effectively reducing the current leakage and improving the refresh characteristics. In the method of manufacturing the recess gate structure, etching is performed twice or more, so as to form a gate recess having varying width in the substrate, and a gate is formed in the gate recess.

1 . A recess gate structure for a transistor in a semiconductor device having a semiconductor substrate having an active areas defined by isolation regions, the recess gate structure comprising:
 a varying-width recess having a first recess width formed in the semiconductor substrate for a first recess depth measured from the surface of the semiconductor substrate and having a second recess width narrower than the first recess width and extending continuously into the semiconductor substrate from the bottom end of the first recess width,   wherein the second recess depth measured from the surface of the semiconductor substrate is longer than the first recess depth measured from the surface of the semiconductor substrate; and   a transistor gate formed in the varying-width recess formed in the semiconductor substrate.