Semiconductor device and method for fabricating the same

摘要

A semiconductor device including a substrate, a plurality of isolation structures, at least a gate structure, a plurality of dummy gate structures and a plurality of epitaxial structures is provided. The substrate has an active area defined by the isolation structures disposed within the substrate. That is, the active area is defined between the isolation structures. The gate structure is disposed on the substrate and located within the active area. The dummy gate structures are disposed on the substrate and located out of the active area. The edge of each dummy gate structure is separated from the boundary of the active area with a distance smaller than 135 angstroms. The epitaxial structures are disposed within the active area and in a portion of the substrate on two sides of the gate structure. The invention also provided a method for fabricating semiconductor device.

主权项

1. A method for fabricating a semiconductor device, comprising:
providing a substrate with a plurality of isolation structures formed therein and defining an active area of the substrate disposed between the isolation structures and having a width W1; forming at least one gate structure and plurality of dummy gate structures on the substrate, the gate structure having a second width W2 and located within the active area, at least one portion of each dummy gate structure located on the corresponding one of the isolation structures, the gate structure separated from each dummy gate structure with a distance D, the first width W1, the second width W2 and the distance D satisfying an inequality: W1 ≧W2+2D; and forming a plurality of epitaxial structures in the substrate on two sides of the gate structure and between the gate structure and the dummy gate structures; wherein before forming the epitaxial structures, further comprises the steps of: forming a sacrificed material layer on the substrate to cover the gate structure; removing a portion of the sacrificed material layer to form a sacrificed spacer on the sidewalls of the gate structure; and removing a portion of the substrate beside the sacrificed spacer to form a plurality of trenches, wherein the epitaxial structures are formed in the trenches; wherein forming the epitaxial structures comprises the steps of:
forming an epitaxial buffer layer in each trench; andforming an epitaxial bulk layer on each epitaxial buffer layer; andforming an epitaxial cap layer on each epitaxial bulk layer.