Electrically Isolated SiGe FIN Formation By Local Oxidation

摘要

A silicon germanium alloy layer is formed on a semiconductor material layer by epitaxy. An oxygen impermeable layer is formed on the silicon germanium alloy layer. The oxygen impermeable layer and the silicon germanium alloy layer are patterned to form stacks of a silicon germanium alloy fin and an oxygen impermeable cap. A shallow trench isolation structure is formed by deposition, planarization, and recessing or an oxygen permeable dielectric material. An oxygen impermeable spacer is formed around each stack of a silicon germanium alloy fin and an oxygen impermeable cap. A thermal oxidation process is performed to convert a lower portion of each silicon germanium alloy fin into a silicon germanium oxide. During the thermal oxidation process, germanium atoms diffuse into unoxidized portions of the silicon germanium alloy fins to increase the germanium concentration therein.

主权项

1. A semiconductor structure comprising:
a semiconductor oxide material portion that contains a semiconductor oxide layer located on a semiconductor material layer and further contains a plurality of semiconductor oxide pedestals that protrudes above said semiconductor oxide layer; a plurality of silicon germanium alloy fins located on said plurality of semiconductor oxide pedestals, wherein each of said plurality of silicon germanium alloy fins is located directly on, and above, one of said plurality of semiconductor oxide pedestals; and a shallow trench isolation structure contacting a top surface of said semiconductor oxide layer and sidewalls of said plurality of semiconductor oxide pedestals, wherein bottommost portions of said plurality of silicon germanium alloy fins are more distal from said semiconductor oxide layer than a planar top surface of said shallow trench isolation structure is from said semiconductor oxide layer.