Question: 20 pts define eot equivalent oxide thickness of a highk...
(20 pts) Define EOT (Equivalent Oxide Thickness) of a high-k dielectric quantitatively (i.e., give a formula for that). You need to express EOT as a function of dielectric constant of a high-k dielectric (k), thickness of high-k dielectric (t), and dielectric constant of SiO2 (kSiO2) (5 pts). Among all high-k dielectric candidates, HfOx has been the most promising one which fulfills the desired properties for CMOS technology. Often times, the high-k dielectric material is used together with a metal gate (instead of poly-silicon gate), and in order to mitigate some mobility and reliability issues of high-k dielectric and silicon interface, an interfacial layer (IL) is purposely added between the silicon channel and the high-k dielectric layer. Thus, the final stack is metal/high-k dielectric/IL/silicon (see the figure below). What is total EOT for this “dual layer” dielectric stack? Assume you have used 3 nm-thick HfOx (kHfOx = 20) as your high-k dielectric material and 0.5 nmthick SiO2 as your IL. (15 pts)
Metal -- Gate
HfOx --- 3nm
IL --- 0.5 nm
Silicon -- Channel