Dielectric effect of a thin SiO 2 interlayer at the interface between Silicon and high- k Oxides

We investigate the dielectric permittivity of SiO2 on Si(100) substrates using a first-principles approach. It is shown that both the static and high-frequency dielectric constants of the oxide overlayer increase when the oxide thickness is reduced. This behavior of the overlayer is found to be well reproduced by a classical two-layer model in which the pure oxide and the suboxide layer are treated as distinct dielectrics. Implications for interfaces between silicon and high-k gate oxides are discussed.

[1]  Alfredo Pasquarello,et al.  Comparison of structurally relaxed models of the Si(001)-SiO2 interface based on different crystalline oxide forms , 1996 .

[2]  D. Vanderbilt,et al.  Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. , 1990, Physical review. B, Condensed matter.

[3]  D. Muller,et al.  The electronic structure at the atomic scale of ultrathin gate oxides , 1999, Nature.

[4]  K. Saraswat,et al.  Electrical and materials properties of ZrO2 gate dielectrics grown by atomic layer chemical vapor deposition , 2001 .

[5]  S. Gangopadhyay,et al.  HfO2 gate dielectric with 0.5 nm equivalent oxide thickness , 2002 .

[6]  Lee,et al.  Ab initio molecular dynamics for d-electron systems: Liquid copper at 1500 K. , 1992, Physical review letters.

[7]  D. Muller,et al.  Atomic scale measurements of the interfacial electronic structure and chemistry of zirconium silicate gate dielectrics , 2001 .

[8]  Masaaki Niwa,et al.  Electrical and physical properties of HfO2 films prepared by remote plasma oxidation of Hf metal , 2003 .

[9]  M. Schulz.  The end of the road for silicon? , 1999, Nature.

[10]  Car,et al.  Generalized-gradient approximations to density-functional theory: A comparative study for atoms and solids. , 1996, Physical review. B, Condensed matter.

[11]  N. Tit,et al.  Electronic states and optical properties of Si/SiO2 superlattices , 1999 .

[12]  Alfredo Pasquarello,et al.  Ab initio molecular dynamics in a finite homogeneous electric field. , 2002, Physical review letters.

[13]  F. Sirotti,et al.  Suboxides at the Si/SiO2 interface: a Si2p core level study with synchrotron radiation , 1997 .

[14]  Jackson,et al.  Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. , 1992, Physical review. B, Condensed matter.

[15]  Car,et al.  Theory of Si 2p core-level shifts at the Si(001)-SiO2 interface. , 1996, Physical review. B, Condensed matter.

[16]  Lee,et al.  Car-Parrinello molecular dynamics with Vanderbilt ultrasoft pseudopotentials. , 1993, Physical review. B, Condensed matter.

[17]  Car,et al.  Unified approach for molecular dynamics and density-functional theory. , 1985, Physical review letters.