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We have grown aluminum nitride thin films by ultrahigh vacuum reactive sputter deposition on Si(111) and Si(001) substrates. We show results of film characterization by Raman scattering, ion beam channeling, and transmission electron microscopy, which establish the occurrence of epitaxial growth of wurtzitic aluminum nitride thin films on Si(111) at temperatures above 600 °C. In contrast, microstructural characterization by transmission electron microscopy shows the formation of highly oriented polycrystalline wurtzitic aluminum nitride thin films on Si(001). Real-time substrate curvature measurements reveal the existence of large intrinsic stresses in aluminum nitride thin films grown on both Si(111) and Si(001) substrates.

He I photoelectron spectra of fluoroethylene, 1,1-difluoroethylene, cis-1,2-difluoroethylene, trans-1,2-difluoroethylene, trifluoroethylene, and perfluoroethylene were obtained over the scattering angle range of 45' to 120' and compared with those of ethylene. Vibrational frequencies of the ionic states were measured and their symmetry modes assigned. The asymmetry parameter /3 as a function of the ionization potential was measured for each molecule. The value of /3 for the first ionization potential band of these molecules was found to decrease monotonically with increasing fluorine substitution. This variation was interpreted as being due to resonance mixing of the lone pair F 1T orbitals with C-C 1T orbitals. The data obtained were used to assign some of the spectral bands observed.

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Real-time measurements of intrinsic stresses during growth of polycrystalline and epitaxial aluminum nitride (AlN) thin films on Si(111) are reported. Our room-temperature measurements on polycrystalline films corroborate previous post-growth measurements. Our high-temperature measurements provide evidence of large intrinsic stresses during epitaxial growth of AlN on Si(111) and insignificant stress relaxation during growth.

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