Epitaxial formation of source and drain regions

摘要

Mechanisms for forming source/drain (S/D) regions of field effect transistors (FETs) are provided. The mechanisms eliminate dislocations near gate corners and gate corner defects (GCDs), and maintain transistor performance. The mechanisms described involve using a post-deposition etch to remove residual dislocations near gate corners after a cyclic deposition and etching (CDE) process is used to fill a portion of the recess regions with an epitaxially grown silicon-containing material. The mechanisms described also minimize the growth of dislocations near gate corners during the CDE process. The remaining recess regions may be filled by another silicon-containing layer deposited by an epitaxial process without forming dislocations near gate corners. The embodiments described enable gate corners to be free of dislocation defects, preserve the device performance from degradation, and widen the process window of forming S/D regions without gate corner defects and chamber matching issues.

主权项

1. A method of forming an integrated circuit, the method comprising:
forming a plurality of gate structures over a substrate; removing portions of the substrate to form recesses adjacent to the plurality of gate structures; depositing a first epitaxial silicon-containing layer in the recesses, wherein depositing the first epitaxial silicon-containing layer uses a cyclic deposition etching (CDE) process, and a top surface of the first epitaxial silicon-containing layer is entirely below a top surface of the substrate; performing an etching process after depositing the first epitaxial silicon-containing layer to remove dislocations near gate corners, wherein an entirety of sidewalls of each recess of the recesses remains covered by the first epitaxial silicon-containing layer following the etching process; and depositing a second epitaxial silicon-containing layer over the first epitaxial silicon-containing layer to form source and drain regions next to the plurality of gate structures, wherein a top surface of the second epitaxial silicon-containing layer is entirely above the top surface of the substrate.