Method of lateral oxidation of nFET and pFET high-K gate stacks

A method for fabricating a semiconductor circuit, the method comprising:

• obtaining a semiconductor structure having a first gate stack and a second gate stack, each containing material layers that include a high-k dielectric layer and a work-function conductor layer;
• oxidizing in a lateral manner (i) the high-k dielectric layer of the first gate stack, such that an oxygen content of the high-k dielectric layer of the first gate stack increases first at the sidewalls of the high-k dielectric layer of the first gate stack, (ii) the high-k dielectric layer of the second gate stack, such that the oxygen content of the high-k dielectric layer of the second gate stack increases first at the sidewalls of the high-k dielectric layer of the second gate stack, and (iii) the work-function conductor layer of the first gate stack, such that oxygen content increases first near the sidewalls of the work-function conductor layer of the first gate stack;
• and
• fabricating (i) a n-type field effect transistor from the first gate stack after laterally oxidizing at least the high-k dielectric layer of the first gate stack, and (ii) a p-type field effect transistor from the second gate stack after laterally oxidizing at least the high-k dielectric layer of the second gate stack.