Replacement channels for semiconductor devices and methods for forming the same using dopant concentration boost

摘要

A replacement channel and a method for forming the same in a semiconductor device are provided. A channel area is defined in a substrate which is a surface of a semiconductor wafer or a structure such as a fin formed over the wafer. Portions of the channel region are removed and are replaced with a replacement channel material formed by an epitaxial growth/deposition process to include a first dopant concentration level less than a first dopant concentration level. A subsequent doping operation or operations is then used to boost the average dopant concentration to a level greater than the first dopant concentration level. The replacement channel material is formed to include a gradient in which the upper portion of the replacement channel material has a greater dopant concentration than the lower portion of replacement channel material.

主权项

1. A method for forming a semiconductor transistor, said method comprising:
defining a channel region in a semiconductor substrate by forming a dummy gate material within a singular dielectric material and conterminous with sidewalls comprised entirely of said singular dielectric material, said channel region associated with a transistor; removing channel material from said channel region by successively removing said dummy gate material then said channel material, thereby forming an opening having said sidewalls, and a recessed portion comprising a void in said semiconductor substrate in said channel region; forming replacement channel material within said void, said replacement channel material comprising one of Ge and SiGe, and including a dopant, and having an as-deposited average dopant concentration less than a first dopant concentration; further doping said replacement channel material with said dopant thereby increasing said average dopant concentration to greater than said first dopant concentration and forming a gradient of dopant concentration in said replacement channel material such that an upper portion of said replacement channel material has a higher dopant concentration than a lower portion of said replacement channel material, and forming a metal transistor gate over said replacement channel material and conterminous with said sidewalls.