Patent ID: 8765556
Filing Date: 2014-07-01
Classification: H01L

Abstract:
1. A method for fabricating a semiconductor device, comprising: providing a semiconductor substrate; forming a gate structure on a surface of the substrate, the gate structure including a first spacer disposed on a sidewall of the gate structure; performing a dry etching to form a recess in the substrate, wherein the recess is U shaped having a side aligned with the first spacer; thereafter forming a second spacer over and on the first spacer disposed on the side wall of the gate structure and on a sidewall of the recess; performing a wet etching with selectivity modulation to modify the recess such that the gate structure is disposed on a portion of the substrate, wherein the portion of the substrate is T shaped having a horizontal region and a vertical region that extends from the horizontal region in a direction away from the surface of the substrate; and filling the recess with a semiconductor material different from the semiconductor substrate.