Semiconductor device and fabrication method thereof

摘要

A method for fabricating a semiconductor device is disclosed. A strained material is formed in a cavity of a substrate and adjacent to an isolation structure in the substrate. The strained material has a corner above the surface of the substrate. The disclosed method provides an improved method for forming the strained material adjacent to the isolation structure with an increased portion in the cavity of a substrate to enhance carrier mobility and upgrade the device performance. In an embodiment, the improved formation method is achieved using an etching process to redistribute the strained material by removing at least a portion of the corner to be located in the cavity.

主权项

1. A method for fabricating a semiconductor device, comprising:
forming an isolation feature in a substrate; forming a gate stack over a surface of the substrate; forming a recess cavity in the substrate, wherein the recess cavity is horizontally positioned between the gate stack and the isolation feature; forming an epitaxial (epi) material in the recess cavity, wherein the epi material has a corner above the recess cavity; performing an etching process to redistribute at least a portion of the corner to be in the recess cavity; and forming a cap layer over the epi material before the step of etching.