Method for increasing a surface area of epitaxial structures in a mixed N/P type fin semiconductor structure by forming multiple epitaxial heads

摘要

A non-planar semiconductor structure includes mixed n-and-p type raised semiconductor structures, e.g., fins, having epitaxial structures grown on top surfaces thereof, for example, epitaxial silicon and silicon germanium, naturally growing into a diamond shape. The surface area of the epitaxial structures is increased by removing portion(s) thereof, masking each type as the other type is grown and then subsequently modified by the removal. The removal may create multi-head (e.g., dual-head) epitaxial structures, together with the neck of the respective raised structure resembling a Y-shape.

主权项

1. A method, comprising:
providing a semiconductor structure, the structure comprising a semiconductor substrate, at least one first raised semiconductor structure of a first type coupled to the substrate, and at least one second raised semiconductor structure of a second type coupled to the substrate; growing at least one first epitaxial structure on a first top surface of one or more of the at least one first raised structure, wherein the at least one first epitaxial structure comprises at least one first epitaxial material; growing at least one second epitaxial structure on a second top surface of one or more of the at least one second raised structure, wherein the at least one second epitaxial structure comprises at least one second epitaxial material; increasing a first surface area of the at least one first epitaxial structure by removing a top portion thereof, the top portion having bottom sides longer than top sides thereof; increasing a second surface area of the at least one second epitaxial structure by removing a top portion thereof, the top portion having bottom sides longer than top sides thereof; wherein the semiconductor structure further comprises a filler layer of at least one filler material conformally surrounding the at least one first raised structure and the at least one second raised structure while exposing the first top surface and the second top surface, and wherein: growing the at least one first epitaxial structure comprises: masking the at least one second raised structure; recessing the exposed first top surface below a top surface of the filler layer; and growing the at least one first epitaxial structure on the recessed first top surface; and growing the at least one second epitaxial structure comprises: masking the at least one first epitaxial structure; recessing the exposed second top surface below a top surface of the filler layer; and growing the at least one second epitaxial structure on the recessed second top surface.