Novel Dielectric Materials for Future Transistor Generations

Abstract

Relations between the electronic properties of high-k materials and electrical characteristics of high-k transistor are discussed. It is pointed out that the intrinsic limitations of these materials from the standpoint of gate dielectric applications are related to the presence of d-electrons, which facilitate high values of the dielectric constant. It is shown that the presence of structural defects responsible for electron trapping and fixed charges, and the dielectrics' tendency for crystallization and phase separation induce threshold voltage instability and mobility degradation in high-k transistors. The quality of the SiO 2-like layer at the high-k/ Si substrate interface, as well as dielectric interaction with the gate electrode, may significantly affect device characteristics.