Self-aligned channel transistor and method for making same

A method for forming a semiconductor device on a semiconductor substrate having a surface, comprising the steps of:

• (A) forming a gate stack on the substrate, the gate stack having a first side and a second side;
• (B) forming a mask layer over the substrate, the mask layer having an opening over the gate stack and over a first and second portions of the substrate at the respective first and second side of the gate stack;
• (C) implanting a first dose of an impurity into the gate stack and the substrate at a first angle relative to a line normal to the surface of the substrate greater than 7 degrees and less than 30 degrees;
• (D) implanting a second dose of the impurity into the gate stack and the substrate at a second angle relative to a line normal to the surface of the substrate, the second angle being less than −7 degrees and greater than −30 degrees;
• and
• wherein the mask layer blocks at least a portion of said first dose and said second dose to a portion of the substrate at the first and second side of the gate stack;
• wherein the impurity is boron and wherein the steps (C) and (D) provide an implant region having a graded concentration profile of about 7×1017 atm/cm3 concentration in the gate stack to about 6.9×1015 atm/cm3 in the substrate underlying the gate stack.