J. Phys. Chem. C 2008, 112, 5185-5189
5185
Hall Mobility Measurements and Chemical Stability of Ultrathin, Methylated Si(111)-on-Insulator Films Jonathan E. Green, Shelley J. Wong, and James R. Heath* Caltech DiVision of Chemistry and Chemical Engineering MC 127-72, 1200 East California BouldeVard, Pasadena, California 91125 ReceiVed: October 30, 2007; In Final Form: January 21, 2008
The chemical and electronic properties of 10-20 nm thick, methylated Si(111)-on-insulator (CH3/Si(111)SOI) thin films, prepared using a wet chemical chlorination/methylation procedure, are investigated. X-ray photoelectron spectroscopy reveals that CH3/Si(111)SOI is resistant to oxidation upon exposure to air and to various device fabrication schemes and associated chemicals. Temperature-dependent Hall mobility measurements yield results that are dependent upon the duration of the chlorination step. For short-time chlorination steps, bulklike mobilities are observed, and the dominant scattering mechanism arises from ionized impurities. For longer time chlorination steps, surface roughness or neutral impurity scattering limit the carrier mobilities.
Introduction As Si devices are dimensionally scaled to the nanometer regime, the properties of the surface play an increasingly prominent role in determining the overall device characteristics.1,2 For example, the electrical transport in ultrathin (
