METHOD OF USING A SACRIFICAL GATE STRUCTURE TO MAKE A METAL GATE FINFET TRANSISTOR

摘要

A self-aligned SiGe FinFET device features a relaxed channel region having a high germanium concentration. Instead of first introducing germanium into the channel and then attempting to relax the resulting strained film, a relaxed channel is formed initially to accept the germanium. In this way, a presence of germanium can be established without straining or damaging the lattice. Gate structures are patterned relative to intrinsic silicon fins, to ensure that the gates are properly aligned, prior to introducing germanium into the fin lattice structure. After aligning the gate structures, the silicon fins are segmented to elastically relax the silicon lattice. Then, germanium is introduced into the relaxed silicon lattice, to produce a SiGe channel that is substantially stress-free and also defect-free. Using the method described, concentration of germanium achieved in a structurally stable film can be increased to a level greater than 85%.

主权项

1. A method, comprising:
forming a plurality of fins extending vertically outward from a surface of a substrate comprised of a first semiconductor material, each of the fins being a contiguous single crystal member extending from the substrate and also being comprised of the first semiconductor material; forming a plurality of gate structures in contact with three sides of each of the fins, each gate structure including a sacrificial gate member; relaxing the fins elastically by segmenting each of the fins into a respective plurality of fin segments, the segmenting exposing sidewalls of each of the fin segments; removing sacrificial gate members from the gate structures; incorporating a second semiconductor material into the fin segments; forming metal gates in the gate structures, each metal gate substantially centered over one of the plurality of fin segments and extending on at least three sides of the respective fin segment; and forming source and drain regions on the exposed sidewalls of the fin segments, with a channel region being within respective fin segments.