TiSi2 was deposited onto both Si and SiO2 substrates by low-pressure chemical vapor deposition. By using both TiCl4 and SiH4 as source gases, the reaction could be controlled to yield either selective TiSi2 on Si substrates only, or blanket silicide films. Experimental conditions providing for selective deposition were investigated. Mass spectroscopy data and thermodynamic calculations were in good agreement with each other and provided rational explanations of observed phenomena. Reaction of TiCl4 vapor with Si yields TiSi2, but is accompanied by excessive Si consumption. This etching reaction may be moderated by increasing the reactor pressure while keeping the substrate temperature around 900 K, and by the introduction of H2 and/or SiH4 into the reactant gas mixture.

Simple thin-film capacitor stacks were fabricated from sputter-deposited doped barium titanate dielectric films with sputtered Pt and/or Ni electrodes and characterized electrically. Here, we report small signal, low frequency capacitance and parallel resistance data measured as a function of applied DC bias, polarization versus applied electric field strength and DC load/unload experiments. These capacitors exhibited significant leakage (in the range 8–210 μA/cm2) and dielectric loss. Measured breakdown strength for the sputtered doped barium titanate films was in the range 200 kV/cm −2 MV/cm. For all devices tested, we observed clear evidence for dielectric saturation at applied electric field strengths above 100 kV/cm: saturated polarization was in the range 8–15 μC/cm2. When cycled under DC conditions, the maximum energy density measured for any of the capacitors tested here was ~4.7 × 10−2 W-h/liter based on the volume of the dielectric material only. This corresponds to a specific energy of ~8 × 10−3 W-h/kg, again calculated on a dielectric-only basis. These results are compared to those reported by other authors and a simple theoretical treatment provided that quantifies the maximum energy that can be stored in these and similar devices as a function of dielectric strength and saturation polarization. Finally, a predictive model is developed to provide guidance on how to tailor the relative permittivities of high-k dielectrics in order to optimize their energy storage capacities.

Raman scattering has been used to measure phonon linewidths and frequencies of a number of high quality diamond crystals. It was found that the defect induced broadening produced a Lorentzian line shape. The smallest Lorentzian linewidth of 1.68 cm−1 at 300 K caused by anharmonicity and defects was obtained for the high pressure synthesized diamond. The linewidths of the diamonds grown by chemical vapor deposition varied, with the best sample having a linewidth of 2.31 cm−1, close to the values for natural diamonds. No measurable phonon frequency shift caused by defects was found.

New apparatus and a new process for the sputter deposition of modified barium titanate thin-films were developed. Films were deposited at temperatures up to 900 °C from a Ba0.96Ca0.04Ti0.82Zr0.18O3 (BCZTO) target directly onto Si, Ni and Pt surfaces and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Film texture and crystallinity were found to depend on both deposition temperature and substrate: above 600 °C, the as-deposited films consisted of well-facetted crystallites with the cubic perovskite structure. A strongly textured Pt (111) underlayer enhanced the (001) orientation of BCZTO films deposited at 900 °C, 10 mtorr pressure and 10% oxygen in argon. Similar films deposited onto a Pt (111) textured film at 700 °C and directly onto (100) Si wafers showed relatively larger (011) and diminished intensity (00ℓ) diffraction peaks. Sputter ambients containing oxygen caused the Ni underlayers to oxidize even at 700 °C: Raising the process temperature produced more diffraction peaks of NiO with increased intensities. Thin-film capacitors were fabricated using ~500 nm thick BCZTO dielectrics and both Pt and Ni top and bottom electrodes. Small signal capacitance measurements were carried out to determine capacitance and parallel resistance at low frequencies and from these data, the relative permittivity (εr) and resistivity (ρ) of the dielectric films were calculated; values ranged from ~50 to >2,000, and from ~104 to ~1010 Ω∙cm, respectively.

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