Interfacial Properties of nMOSFETs With Different Al₂O₃ Capping Layer Thickness and TiN Gate Stacks

In this article, the interfacial properties of nMOSFETs with different thickness high- $\kappa $ Al2O3 capping layer on an 8-nm SiO2 and TiN gate stacks have been investigated using electrical measurement and low-frequency noise at room temperature. It is shown that the predominant 1/ ${f}$ noise is governed by the number fluctuations mechanism. It is indicated that: 1) presence of an Al2O3 capping layer increases the noise power spectral density and, hence, the oxide trap density has an influence on the low-field mobility further and 2) effective work-function and the threshold voltage of nMOSFET should be modulated using the high- $\kappa $ Al2O3 capping layers.