Structure and method for advanced bulk fin isolation

摘要

A non-planar semiconductor structure containing semiconductor fins that are isolated from an underlying bulk silicon substrate by an epitaxial semiconductor stack is provided. The epitaxial semiconductor material stack that provides the isolation includes, from bottom to top, a semiconductor punch through stop containing at least one dopant of a conductivity type which differs from the conductivity type of the particular device region that the semiconductor fin is formed in, and a semiconductor diffusion barrier layer containing no n- or p-type dopant.

主权项

1. A method of forming a semiconductor structure, said method comprising:
providing a bulk silicon substrate comprising a device region for a p-type semiconductor device of a first conductivity type; recessing an exposed portion of said bulk silicon substrate in said device region to expose a sub-surface of said bulk silicon substrate; forming a semiconductor material stack of, from bottom to top, a semiconductor punch through stop layer containing at least one dopant of a second conductivity type which is opposite from said first conductivity type, a semiconductor diffusion barrier layer containing no n- or p-type dopant, and an epitaxial semiconductor layer on said sub-surface of said bulk silicon substrate; and forming a plurality of semiconductor fins in said device region, wherein each semiconductor fin of said plurality of semiconductor fins comprises, from bottom to top, a remaining portion of said semiconductor punch through stop layer, a remaining portion of said semiconductor diffusion barrier, and a remaining portion of said epitaxial semiconductor layer, wherein said semiconductor punch through stop layer comprises a first carbon-doped silicon layer, said semiconductor diffusion barrier layer comprises a second carbon-doped silicon layer, and said epitaxial semiconductor layer comprises silicon or a silicon germanium alloy.