Performing enhanced cleaning in the formation of MOS devices

摘要

A method includes etching a semiconductor substrate to form a recess, wherein the recess extends from a top surface of the semiconductor substrate into the semiconductor substrate. An enhanced cleaning is then performed to etch exposed portions of the semiconductor substrate. The exposed portions are in the recess. The enhanced cleaning is performed using process gases including hydrochloride (HCl) and germane (GeH4). After the enhanced cleaning, an epitaxy is performed to grow a semiconductor region in the recess.

主权项

1. A method comprising:
etching a semiconductor substrate to form a recess using a wet etch, with exposed surfaces of the semiconductor substrate in the recess comprising a first (111) bottom surface and a second (111) bottom surface in physical contact with the first (111) bottom surface, wherein the recess extends from a top surface of the semiconductor substrate into the semiconductor substrate; after the wet etch, performing an enhanced cleaning to etch exposed portions of the semiconductor substrate, with the enhanced cleaning being performed using a dry etch, wherein the exposed portions are in the recess, and wherein the enhanced cleaning is performed using process gases comprising hydrochloride (HCl) and germane (GeH4); and after the enhanced cleaning, performing an epitaxy to grow a semiconductor region in the recess.