Role of interface dipole in metal gate/high-k effective work function modulation by aluminum incorporation

The interface dipole and its role in the effective work function (EWF) modulation by Al incorporation are investigated. Our study shows that the interface dipole located at the high-k/SiO2 interface causes an electrostatic potential difference across the metal/high-k interface, which significantly shifts the band alignment between the metal and high-k, consequently modulating the EWF. The electrochemical potential equalization and electrostatic potential methods are used to evaluate the interface dipole and its contribution. The calculated EWF modulation agrees with experimental data and can provide insight to the control of EWF in future pMOS technology.

National Natural Science Foundation of China 50802005 Program for New Century Excellent Talents in University NCET-08-0029 Ph.D. Program Foundation of Ministry of Education of China 200800061055 Hong Kong Research Grants Council (RGC) General Research Funds (GRF) CityU 112608 Our work was financially supported by National Natural Science Foundation of China (Grant No. 50802005), Program for New Century Excellent Talents in University (Grant No. NCET-08-0029), Ph.D. Program Foundation of Ministry of Education of China (Grant No. 200800061055), and Hong Kong Research Grants Council (RGC) General Research Funds (GRF) (Grant No. CityU 112608).