Isolation Structure of Fin Field Effect Transistor

摘要

A representative fin field effect transistor (FinFET) includes a substrate having a major surface; a fin structure protruding from the major surface having a lower portion comprising a first semiconductor material having a first lattice constant; an upper portion comprising the first semiconductor material. A bottom portion of the upper portion comprises a dopant with a first peak concentration. A middle portion is disposed between the lower portion and upper portion, where the middle portion comprises a second semiconductor material having a second lattice constant different from the first lattice constant. An isolation structure surrounds the fin structure, where a portion of the isolation structure adjacent to the bottom portion of the upper portion comprises the dopant with a second peak concentration equal to or greater than the first peak concentration.

主权项

1. A method of fabricating a fin field effect transistor (FinFET), the method comprising:
providing a substrate having a shallow trench isolation (STI) region surrounding a semiconductor fin, wherein the substrate comprises a first semiconductor material having a first lattice constant; performing a first implantation process to the STI region, whereby a portion of the STI region comprises a dopant with a first peak concentration; recessing the semiconductor fin to form a fin recess; selectively growing a second semiconductor material partially filling the fin recess, wherein the second semiconductor material has a second lattice constant different from the first lattice constant; selectively growing a third semiconductor material filling the fin recess; and performing a second implantation process to the third semiconductor material, wherein a bottom portion of the third semiconductor material comprises the dopant with a second peak concentration equal to or less than the first peak concentration.