Structural morphology and electronic properties of the Si-Cr interface

Abstract

Photoemission studies {12(hv(135eV) of room-temperature formation of the Si-Cr interface show reactive behavior with atomic intermixing and dramatic modifications of the metal-derived d density of states. Self-consistent augmented-spherical-wave calculations of the total and I-projected densities of states for the silicides Cr3Si, CrSi, and CrSi3 in simplified cubic lattice structures allow an identification of general trends in the electronic structure upon Si-Cr heteropolar bond formation. These experimental and theoretical results suggest an interface morphology where a Si-rich intermixed phase is present for a depth of =10 monolayers between the Si crystal and the unreacted Cr film. Evidence of Si segregation in the top layers of the Cr film is provided.

Synchrotron radiation photoemission study of metal overlayers on hydrogenated amorphous silicon at room temperature

“…For a photoemission study of a Cr/c-Si interface formed by evaporation at room temperature, the binding energy of the bonding state shifted progressively toward the Fermi level with increasing coverage. The negative shift appeared only in a reacted Cr-Si region whose thickness was given as 10-15 ML by Franciosi et al [107] and as 25 ML by Wetzel et al [108].…”

“…Density-of-states calculations [107] infer that the bonding state in a Si-rich silicide has a higher binding energy than in a Cr-rich silicide. Experimental study of a definite silicide like CrSig using photoemission reveals the binding energies of the bonding and non-bonding states to be 2.2 eV and 0.2 eV, respectively [108].…”

“…Experimental study of a definite silicide like CrSig using photoemission reveals the binding energies of the bonding and non-bonding states to be 2.2 eV and 0.2 eV, respectively [108]. Different values have also been given, 1.7 and 0.3 eV, respectively [107]. Wetzel et al fiirther showed the bonding and non-bonding states for CrSi were 1.6 and 0.2 eV, respectively [108].…”

“…The Cr Bd -Si 3p bonding and non-bonding structures with different silicide stoichiometrics in the Cr/c-Si system have been studied, theoretically [107] and experimentally [107,108]. Density-of-states calculations [107] infer that the bonding state in a Si-rich silicide has a higher binding energy than in a Cr-rich silicide.…”

“…Detailed photoemission studies of the electronic structure of the Cr/c-Si interface have been reported by a number of groups [106][107][108]. The consensus picture for the evolution of the interface is an initial inert Cr layer, followed by an intermixed layer and, ultimately, the development of bulk Cr metal, with increasing coverage.…”