Dielectric punch-through stoppers for forming FinFETs having dual fin heights

摘要

A semiconductor structure includes a semiconductor substrate having a first portion and a second portion. A first Fin field-effect transistor (FinFET) is formed over the first portion of the semiconductor substrate, wherein the first FinFET includes a first fin having a first fin height. A second FinFET is formed over the second portion of the semiconductor substrate, wherein the second FinFET includes a second fin having a second fin height different from the first fin height. A top surface of the first fin is substantially level with a top surface of the second fin. A punch-through stopper is underlying and adjoining the first FinFET, wherein the punch-through stopper isolates the first fin from the first portion of the semiconductor substrate.

主权项

1. A semiconductor structure comprising:
a semiconductor substrate; a first shallow trench isolation (STI) region over the semiconductor substrate and having a first top surface and a first bottom surface; a second STI region over the semiconductor substrate and having a second top surface substantially level with the first top surface of the first STI region, and a second bottom surface substantially level with the first bottom surface of the first STI region; a first fin adjacent to, and above, the first STI region; a second fin adjacent to, and above, the second STI region, wherein the second fin has a top surface substantially level with a top surface of the first fin, and wherein the first fin and the second fin have different fin heights; a first lower fin underlying and vertically aligned to the first fin, wherein the first lower fin has a bottom surface substantially level with the first bottom surface of the first STI region; and a first punch-through stopper between and adjoining the first fin and the first lower fin, wherein the first punch-through stopper comprises an oxide of a semiconductor material of the first fin.