Locally raised epitaxy for improved contact by local silicon capping during trench silicide processings

摘要

A low resistance contact to a finFET source/drain can be achieved by forming a defect free surface on which to form such contact. The fins of a finFET can be exposed to epitaxial growth conditions to increase the bulk of semiconductive material in the source/drain. Facing growth fronts can merge or can form unmerged facets. A dielectric material can fill voids within the source drain region. A trench spaced from the finFET gate can expose the top portion of faceted epitaxial growth on fins within said trench, such top portions separated by a smooth dielectric surface. A silicon layer selectively formed on the top portions exposed within the trench can be converted to a semiconductor-metal layer, connecting such contact with individual fins in the source drain region.

主权项

1. A method to form a finFET, the method comprising:
on an initial structure that includes (a) a gate formed over a set of fins on a substrate and (b) at least two of said set extend into a S/D region adjacent to said gate, forming epitaxial material on said at least two of said set within said S/D region; covering said epitaxial material with a dielectric layer; forming a cavity in said dielectric material to expose a top area of said epitaxial material, wherein said cavity extends generally parallel to said gate and is separated from said gate by a region of said dielectric material; growing a silicon cap on said top area; and forming a first conductive bar in said cavity.