Epitaxy everywhere based self-aligned direct backside contact

Abstract

Self-aligned direct backside contacts by an epitaxy everywhere under source/drain region approach are provided. In one aspect, a semiconductor device includes: a field-effect transistor(s) on a backside interlayer dielectric; an epitaxial contact placeholder in the backside interlayer dielectric that directly contacts a first source/drain region of the field-effect transistor(s); and a self-aligned direct backside contact in the backside interlayer dielectric that directly contacts a second source/drain region of the field-effect transistor(s). The epitaxial contact placeholder extends a distance dinto the backside interlayer dielectric from the first source/drain region, and the self-aligned direct backside contact extends a distance dinto the backside interlayer dielectric from the second source/drain region, where d>d. The field-effect transistor(s) can include a stack of active layers surrounded by a gate, and the first/second source/drain regions on opposite sides thereof. A method of fabricating the present semiconductor device is also provided.