Patent ID: 7208397

Claim:
A method, comprising: implanting a first ion species into a semiconductor region having formed thereon a gate electrode structure having a source-side portion and a drain-side portion, said first ion species forming a first halo implantation region having a first overlap at said source-side portion, said overlap being asymmetric with respect to said gate electrode structure along a gate length direction wherein implanting said first ion species comprises a first implantation step with a first implantation energy, a first dose and a first non-zero tilt angle with respect to a direction perpendicular to a surface of said substrate, and a second implantation step with a second implantation energy, a second dose and a second non-zero tilt angle with respect to a direction perpendicular to a surface of said substrate, said first implantation energy being less than said second implantation energy, said first dose being higher than said second dose, and said first and second non-zero tilt angles being directed at said source-side portion and away from said drain-side portion; and implanting a second ion species into said semiconductor region and into said first implantation region to form a second implantation region that is asymmetric with respect to said gate electrode structure along the gate length direction, wherein said first and second ion species are of opposite conductivity type.