As the technology for diamond film preparation by plasma-assisted CVD and related procedures has advanced, Raman spectroscopy has emerged as one of the principal characterization tools for diamond materials. Cubic diamond has a single Raman-active first order phonon mode at the center of the Brillouin zone. The presence of sharp Raman lines allows cubic diamond to be recognized against a background of graphitic carbon and also to characterize the graphitic carbon. Small shifts in the band wavenumber have been related to the stress state of deposited films. The effect is most noticeable in diamond films deposited on hard substrates such as alumina or carbides. The Raman line width varies with mode of preparation of the diamond and has been related to degree of structural order. The Raman spectrum of hexagonal diamond (lonsdaleite) is distinct from that of the cubic diamond and allows it to be recognized.

Implantation of nitrogen at 150 KeV and a dose of 1 ⊠ 1018/cm2 into (110) silicon results in the formation of an amorphized layer at the mean ion range, and a deeper tail of nitrogen ions. Annealing studies show that the amorphized layer recrystallizes into a continuous polycrystalline Si3N4 layer after annealing for 1 h at 1200 °C. In contrast, the deeper nitrogen fraction forms discrete precipitates (located 1μm below the wafer surface) in less than 1 min at this temperature. The arcal density of these precipitates is 5 ⊠ 107/cm2 compared with a nuclei density of 1.6 ⊠ 105/cm2 in the amorphized layer at comparable annealing times. These data suggest that the nucleation step limits the recrystallization rate of amorphous silicon nitride to form continuous buried nitride layers. The nitrogen located within the damaged crystalline silicon lattice precipitates very rapidly, yielding semicoherent crystallites of β–Si3N4.

Fourier transform infrared spectroscopy (FT–IR) forms the basis for determining the morphological composition of mixtures containing alpha, beta, and amorphous phases of silicon nitride. The analytical technique, involving multiple linear regression treatment of Kubelka-Munk absorbance values from diffuse reflectance measurements, yields specific percent composition data for the amorphous phase as well as the crystalline phases in ternary mixtures of 0–1% by weight Si3N4 in potassium bromide.

Thermal and anodic oxide films of beta silicon carbide are analyzed using Auger electron spectroscopy. Auger depth-composition profiles are obtained in order to determine the chemical composition of the oxide films. The position and shape of silicon spectral peaks are used to estimate the chemical bonding of the oxide constituents. It is found that the wet thermal oxide is almost stoichiometric but contains about 14% carbon. Dry oxide, on the other hand, has less than 3% carbon but is highly nonstoichiometric. The carbon content in the anodic oxide is 12%. Anodic oxide films, like dry-oxide films, are nonstoichiometric. A model of the SiC oxidation process is presented.

Titanium carbide may be readily produced in high purity via direct reaction between the solid phases of titanium and carbon in the process of combustion synthesis, also known as self-propagating high-temperature synthesis (SHS). The high temperatures generated by this exothermic reaction (<3000 °C) melt the titanium phase which subsequently flows to and reacts with the solid carbon. As a result, with lightly or uncompressed green bodies a product is obtained which retains most of the carbon precursor powder morphology down to the μm scale. The effect of three distinctly different carbon precursor powders on the final titanium carbide morphology has been examined. Subsequent effects of particle size and microstructure on the quality of the titanium carbide product are also noted.

The solid-phase epitaxy of LiNbO3 following ion implantation of Ti dopant for the purpose of producing optical waveguides has been studied. Implanting 360-keV Ti at liquid nitrogen temperature produces a highly damaged region extending to a depth of about 400 nm. This essentially amorphous region can be recrystallized epitaxially by annealing in a water-saturated oxygen atmosphere at temperatures near 400 °C. though complete removal of all irradiation-induced damage requires temperatures in excess of 600 °C. The activation energy of the regrowth is 2.0 eV for implanted fluences below 3 ⊠ 1016 Ti/cm2. At higher fluences the regrowth proceeds more slowly, and Ti dopant segregates at the regrowth interface. Complete recrystallization following high-dose implantation requires annealing temperatures in excess of 800 °C.

The thermodynamic activity of sodium oxide (Na2O) in the Nasicon solid solution series, Na1+xZr2SixO12, has been measured in the temperature range 700–1100 K using solid state galvanic cells: Pt|CO2 + O2|Na2CO3∥Na1+xZr2SixP3−xO12∥(Y2O3)ZrO2∥In + In2O3|Ta, Pt for 1 ≤ ⊠ ≤ 2.5, and Pt∥CO2 + O2∥Na2CO3∥β-alumina∥Na1+xZr2SixP3−xO12∥Ar + O2∥Pt for x = 0, 0.5, 2.5, and 3. The former cell, where the Nasicon solid solution is used as an electrolyte along with yttria-stabilized zirconia, is well suited for Nasicon compositions with high ionic conductivity. In the latter cell, β-alumina is used as an electrolyte and the Nasicon solid solution forms an electrode. The chemical potential of Na2O is found to increase monotonically with x at constant temperature. The partial entropy of Na2O decreases continuously with x. However, the partial enthalpy exhibits a maximum at x = 2. This suggests that the binding energy is minimum at the composition where ionic conductivity and cell volume have maximum values.

Silicon-29 NMR is used to study the structural intermediates in tetramethyl and tetraethyl orthosilicate (TMOS and TEOS) low pH sol-gel reactions. Differences in the number of compact ring structures are related to differences in gel times. Reactions are followed at various silicon: water: acid molar ratios.

Molecular dynamics simulations (MD) employing multibody potentials were used to simulate sodium trisilicate glass (Na2O·3SiO2). A multibody term has been added to a pair potential in order to incorporate the bond directionality which is expected for the partially covalent silicate structure. The structure of the glass was analyzed and results were compared to those found using two-body potentials and molecular statics, as well as to experimental results found using x-ray diffraction, XPS, NMR, and EXAFS. Current results compared favorably to experiment and showed improvement over results obtained using two-body potentials. Nearest neighbor distances and coordination numbers agreed well with published data. Although two-body potentials normally show overcoordinated silicon (>4.3) and broad O–Si–O tetrahedral angle distributions, in this study all silicon exhibited tetrahedral coordination (4.0) and the O–Si–O bond angle distribution was markedly sharpened. The number of nonbridging oxygens was shown to be nearly equal to the number of sodium ions present, and a reasonable distribution of Qc species was found. The overall structure closely resembled the modified network structure of glass proposed experimentally, with silicon tetrahedra remaining intact and sodium ions breaking up the network through the creation of nonbridging oxygens.

In the present work we characterize sputtered iridium oxide films (SIROF) by differential scanning calorimetry (DSC), x-ray, and impedance spectroscopies. We show that a crystallization transition occurs at ca, 230 °C, and suggest a bilayer model for the sputtered film. The transition results in a crystalline mixture of iridium metal and iridium oxide; this suggests a decomposition-crystallization process of the type 2Ir2O3 ⇉ Ir + 3IrO2. In the bilayer model proposed by us, the layer closer to the substrate would reflect the combined influence of the sputtering conditions and of the substrate, while the properties of the second layer depend on the sputtering conditions alone. The bilayer structure is supported by results obtained by impedance spectroscopy.

A method has been developed for determining the equilibrium phase composition of multicomponent systems at subsolidus conditions and atmospheric pressure, based on the knowledge of binary phase compatibilities and on information concerning the existence and stoichiometry of ternary and higher order compounds. The method, combined with material balance, enables computation of the changes of equilibrium phase compositions of fired products dependent on the proportions of multicomponent raw materials; the procedure is useful for assessing the exploitability of industrial wastes for production of binding materials and ceramics. It is also possible to find the raw material mixture composition needed for the desired phase composition of the fired product.

Polyacrylonitrile (PAN) films have been fabricated by both spin and solvent casting techniques, and pyrolyzed to produce carbon films in the thickness range of 200–50000 Å. These films have higher electrical conductivities than carbon films produced from most other precursors at similar temperatures. The chemical structure of the films at different stages of processing was investigated by UV, IR, Raman, and XPS spectroscopies. An extra degree of control over the final electrical conductivity was obtained by varying the PAN content of copolymer precursors. Oxidation rates and an activation energy were determined. Finally, processing techniques are described which allow both dry and wet film transfer and lithographic patterning.