Influence of sidewall spacer on threshold voltage of MOSFET with high-k gate dielectric

In this paper, an analytical expression of the gate-dielectric fringing-potential distribution is derived for high-k gate-dielectric MOSFET through a conformal-mapping transformation method for the first time. Based on the fringing-potential distribution, the threshold-voltage model of the MOSFET is improved, and the influence of sidewall spacer on the threshold voltage is discussed in detail. Calculated results indicate that low-k sidewall spacer can alleviate the fringing-field effect.