Patent ID: 7172954

Claim:
A method of forming extension regions in a semiconductor device, the method using two implantation steps comprising: providing a semiconductor body having a top surface; performing a first ion implantation of dopants of a first conductivity type into specific areas of the semiconductor body, the first ion implantation step being performed at a first dose and a first implant energy to form said extension regions between said top surface and a first depth in said specific areas; performing a second ion implantation of dopants of the first conductivity type into the same specific areas of the semiconductor body to extend the entire of said extension regions to a second depth that is greater than said first depth, the second ion implantation step being performed at a second dose and a second implant energy, the second dose being lower than the first dose and the second implant energy being higher than the first implant energy; and activating the dopants by heating the semiconductor body for a time such that the dopants substantially do not diffuse.