Asymmetric cyclic deposition and etch process for epitaxial formation mechanisms of source and drain regions

摘要

The embodiments of mechanisms for forming source/drain (S/D) regions of field effect transistors (FETs) described uses Cl2 as an etchant during the epitaxial formation of the S/D regions. The mechanisms involve using an asymmetric cyclic deposition and etch (ACDE) process that forms a preparation layer enable epitaxial growth of the following epitaxial layer with transistor dopants. The mechanisms also involve soaking the surface of substrate with dopant-containing precursors to enable sufficient incorporation of transistor dopants during the epitaxial growth of the S/D regions. By using Cl2 as etchants, the mechanisms also enables high throughput of the epitaxial growth of the S/D regions.

主权项

1. A method comprising:
forming a gate structure over a substrate; etching the substrate to form a recess adjacent to the gate structure; and epitaxially growing a first material in the recess using an asymmetric cyclic deposition and etching (ACDE) process, wherein each deposition process of the ACDE process is performed separately from each subsequent etch process of the ACDE process, wherein the ACDE process includes a plurality of CDE unit cycles, processes in a first CDE unit cycle being free of a p-type dopant soak process performed in subsequent CDE unit cycles.