Oxidation of NiSi and Ni(Pt)Si: Molecular vs. Atomic Oxygen

Abstract

X-ray photoelectron spectroscopy (XPS) has been used to characterize the reactivities of clean, stoichiometric NiSi and Ni(Pt)Si films on n-doped Si(100) substrates in O 2 , and in O+O 2 environments. In the presence of O+O 2 , NiSi and Ni(Pt)Si form Ni silicate and Pt silicate overlayers, respectively, with oxide/silicate overlayer thicknesses of 41(4) Å (NiSi) and 28(3) Å (Ni(Pt)Si) after 4.5x10 4 L exposure. Exposure to O 2 yields, for each material, a ~7(1) Å thick SiO 2 overlayer without transition metal oxidation. O+O 2 induces rapid Si oxidation, formation of metal-rich silicides, and then the kinetically-driven oxidation of Ni or Pt to form a silicate. This may pose significant processing problems in silicate removal and unwanted Ni diffusion into other areas of the device.

Graphene/Substrate Charge Transfer Characterized by Inverse Photoelectron Spectroscopy

“…Briefly, a MgO(111) substrate 1 cm in diameter and 0.5 mm thick was cleaned at room temperature by exposure to atomic oxygen from a commercially available thermal catalytic cracker (Oxford Applied Instruments). A flux of dissociated C 2 H 4 was supplied from the same source, which has also been described previously. , XPS spectra were acquired at a constant pass energy (44 eV) using Mg Kα radiation and analyzed using commercial software (ESCATOOLS) according to standard methods.…”

“…A flux of dissociated C 2 H 4 was supplied from the same source, which has also been described previously. 19,20 XPS spectra were acquired at a constant pass energy (44 eV) using Mg KR radiation and analyzed using commercial software (ESCA-TOOLS) according to standard methods.…”