Patent ID: 8288222

Claim:
A method of fabricating a semiconductor structure comprising: forming a high k gate dielectric atop a semiconductor substrate including a first device region and a second device region; selectively forming a first surface threshold voltage adjusting region in one portion of the high k gate dielectric located within 3 nm or less from an upper surface of the high k gate dielectric in either the first device region or the second device region; and selectively forming a second surface threshold voltage adjusting region in another portion of the high k gate dielectric located within 3 nm or less from the upper surface of the high k gate dielectric in the other of the first device region or the second device region not including the first surface threshold voltage adjusting region, wherein said selectively forming the first and second threshold voltage adjusting regions comprises: forming a first threshold voltage adjusting material atop the high k gate dielectric in both device regions, forming a first patterned mask atop the first threshold voltage adjusting material in one of the device regions, performing an inert ion cluster beam implant process which drives a first threshold voltage adjusting impurity from said first threshold voltage adjusting material not protected by the first patterned mask into a portion of said high k gate dielectric, removing the first patterned mask and the first threshold voltage adjusting material, forming a second threshold voltage adjusting material atop the high k gate dielectric in both device regions, forming a second patterned mask atop the second threshold voltage adjusting material in the device region including the first threshold voltage adjusting impurity, performing another inert ion cluster beam process which drives a second threshold voltage adjusting impurity from said second threshold voltage adjusting material not protected by the second patterned mask into another portion of the high k gate dielectric, and removing the second patterned mask and the second threshold voltage adjusting material.