Determination of effective oxide thickness of a plurality of dielectric materials in a MOS stack

A method for determining a respective effective oxide thickness for each of a first dielectric structure comprised of a first dielectric material and a second dielectric structure comprised of a second dielectric material that form a MOS (metal oxide semiconductor) stack, the method including the steps of:

• A. forming a first plurality of test MOS (metal oxide semiconductor) stacks with each test MOS stack being comprised of a respective first dielectric structure comprised of said first dielectric material and a respective second dielectric structure comprised of said second dielectric material;
• B. varying a respective deposition time for forming said respective first dielectric structure corresponding to each of said first plurality of test MOS stacks during said step A such that a respective first effective oxide thickness of said respective first dielectric structure varies for said first plurality of test MOS stacks;
• C. maintaining a respective second effective oxide thickness of said respective second dielectric structure to be substantially same for each of said first plurality of test MOS stacks during said step A;
• D. measuring a respective total effective oxide thickness, EOTMOS, for each of said first plurality of test MOS stacks;
• E. generating a first graph having total effective oxide thickness as a first axis and having deposition time for forming said first dielectric structure as a second axis by plotting said respective total effective oxide thickness, EOTMOS, versus said respective deposition time for forming said respective first dielectric structure for each of said first plurality of test MOS stacks;
• and
• F. determining said respective second effective oxide thickness of said respective second dielectric structure that is substantially same for each of said first plurality of test MOS stacks from an intercept of said first axis of total effective oxide thickness when deposition time for forming said first dielectric structure of said second axis is substantially zero in said first graph.