Theoretical Evaluation of Zirconia and Hafnia as Gate Oxides for Si Microelectronics

Abstract

Parameters determining the performance of the crystalline oxides zirconia (${\mathrm{Z}\mathrm{r}\mathrm{O}}_2$) and hafnia (${\mathrm{H}\mathrm{f}\mathrm{O}}_2$) as gate insulators in nanometric Si electronics are estimated via ab initio calculations of the energetics, dielectric properties, and band alignment of bulk and thin-film oxides on Si (001). With their large dielectric constants, stable and low-formation-energy interfaces, large valence offsets, and reasonable (though not optimal) conduction offsets (electron injection barriers), zirconia and hafnia appear to have considerable potential as gate oxides for Si electronics.