P. F. Lyman | Searcharxiv

arXiv2002

Hafnium silicide formation on Si(001)

Thick (~50 nm) films of Hf were evaporated onto bare and oxidized Si(001) samples, and thin (~monolayer) films of Hf were evaporated onto clean Si(001)-(2x1) surfaces. Upon annealing to 1000$^/circ$C, films of HfSi2 were formed after reaction times that depended upon the surface condition of the substrate before deposition. The chemical state of the reacted surfaces were characterized using x-ray photoelectron spectroscopy, and the shifts in binding energy upon silicide formation were recorded. Even for thick films, low-energy electron diffraction (LEED) revealed that the (2x1) pattern of the Si substrate returned, suggesting that 3-dimensional islanding of the HfSi2 film had occurred. The islanding behavior was confirmed for thin films using LEED and x-ray standing waves. Streaking in the LEED patterns for the thick films suggest that the island morphology is influenced by the underlying Si substrate.

cond-mat.mtrl-sci↗

arXiv2002

Production of a hafnium silicate dielectric layer for use as a gate oxide by solid-state reaction

The formation of hafnium silicate films (HfSixOy) for use as gate oxides with large dielectric constant by solid state reaction of Hf metal and SiO2 was investigated. Thin, fully reacted silicate films could be formed, and were thermally stable in vacuum to temperatures in excess of 800 C. The interface between a hafnium silicate layer and the silicon substrate was shown to be stable against SiO2 formation. The results suggest a new processing route for production of a gate insulator having low equivalent oxide thickness.

cond-mat.mtrl-sci↗