Patent ID: 8946035
Filing Date: 2015-02-03
Classification: H01L

Abstract:
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.