Patent ID: 8211784
Filing Date: 2012-07-03
Classification: H01L

Abstract:
1. A method for manufacturing a semiconductor device, comprising: providing a substrate; forming two main carbon-rich regions and two additional carbon-rich regions in said substrate, wherein said main carbon-rich regions are separately located in said substrate so that a channel region is located between said carbon-rich regions, said additional carbon-rich regions being respectively located underneath said main carbon-rich regions, and the carbon concentration of said main carbon-rich regions is higher than the carbon concentration of said additional carbon-rich regions; wherein an absolute value of a gradient of said additional carbon-rich regions is adjusted to be smaller than an absolute value of a gradient of a bottom portion of said main carbon-rich regions when both said additional carbon-rich regions and said bottom portion of said main carbon-rich regions have gradually decreasing carbon concentrations with increasing depth measured from a top surface of said main carbon-rich regions.