Patent ID: 8153514

Claim:
A method of forming a gate stack structure having enhanced mobility comprising: providing a stack including an interlayer comprising at least atoms of Si and O and a Hf-containing high-k gate dielectric located on an upper surface of said interlayer; and converting said stack into a gate stack structure including a regrown and intermixed interlayer comprising Hf in atomic weight % ranging from 3% to 15%, O in an atomic weight % ranging from 50% to 65%, nitrogen in an amount from 1×10 14 atoms/cm 2 to 3×10 15 atoms/cm 2 , and a remainder of Si, said gate stack structure having an interface state density, as measured by charge pumping, of about 8×10 10 charges/cm 2 or less, a peak mobility of about 250 cm 2 /V-s or greater and substantially no mobility degradation at about 6.0×10 12 inversion charges/cm 2 or greater, wherein said converting includes annealing said stack at a temperature of about 800° C. or greater.