Thin hydrogenated amorphous silicon carbide (a-SiC:H) films were grown at substrate temperatures ranging from 200 K to 600 K by remote ECR plasma-enhanced CVD. Mono- and trimethylsilane were used as single source precursors. The films grown using both precursors were compared as a function of temperature by in situ multiple internal reflection Fourier transform infrared (MIR-FTIR) spectroscopy. The difference in growth temperature leads to changes in both the hydrogen content and the composition of the film. At low growth temperature, films incorporate high concentrations of intact methyl group and a mixture of SiHx (x=1–3) groups, with a polysilane-like structure. At higher temperatures, the hydrogen content decreases. This decrease is observed in two different ways: (1) a loss of highly hydrogenated SiHx groups (SiH3 or SiH2); and (2) a shift from methyl groups to CH2 and CH bonding. However, the temperature dependence of each functional group is found to be different for the two precursors.

Amorphous silicon carbide (SiC) was deposited by plasma enhanced chemical vapor deposition (PECVD) in an Applied Materials (AMT5000) tool from sources of trimethylsilane (3MS) and either argon or nitrogen. A deposition rate of ≈ 800 nm/min on a 150 mm silicon wafer was achieved at 350°C. Process conditions investigated were temperature (200–400°C), power (100–600W), pressure (2–8 torr), gas flow rates, and spacing. Various process condition regimes generated a high particle count that was eliminated by controlling parameters of pressure and spacing. Ellipsometry and n&k Analyzer techniques determined the index of refraction. The index of refraction was in agreement between both tools and range from 1.79–2.36 depending on the 3MS flow (25–100 seem) and carrier gas. A Prometrix FT500 with a fixed index of refraction measured 49 points of thickness determined the uniformity. The SiC films stoichiometric composition was measured by X-ray Photoelectron Spectroscopy (XPS). Small quantities of oxygen or nitrogen were found. Additional properties examined were crystallinity, stress, and pinhole density. Dielectric constant was measured by CV techniques.

AlxTi1-xN film growth has been studied by a organometallic chemical vapor deposition and in-situ X-ray photoelectron spectroscopy. Terakis(dimethylamido)titanium (TDMAT) and dimethyl aluminum hydride (DMAH) were used as the Ti, N and Al precursors. AlTiN film growth was observed on SiO2/Si(100) with substrate temperatures between 200 and 400 °C. The Al content in the film is controlled by the ratio of partial pressures of the two precursors in the gas phase. The metal to C to N ratio is approximately constant at 1:1:1 for most conditions studied. The chemical states of Ti, C, and N in AlxTi1-xN and titanium-carbo-nitride (TiCN) films are identical, while the Al chemical state is nitride at low, but increasingly carbidic at high Al concentration. The initial growth rate on SiO2 was significantly suppressed by the presence of DMAH. At lower growth temperatures, the DMAH effect is more severe. Good step coverage was observed for AlxTi1-xN on 0.3 μm vias with a 3:1 aspect ratio.

Chalcopyrite CuInS2 is a direct band gap semiconductor (1.5 eV) that has potential applications in photovoltaic thin film and photoelectrochemical devices. We have successfully employed spray chemical vapor deposition using the previously known, single-source, metalorganic precursor, (Ph3P)2CuIn(SEt)4, to deposit CuInS2 thin films. Stoichiometric, polycrystalline films were deposited onto fused silica over a range of temperatures (300–400 °C). Morphology was observed to vary with temperature: spheroidal features were obtained at lower temperatures and angular features at 400 °C. At even higher temperatures (500 °C), a Cu-deficient phase, CuIn5S8, was obtained as a single phase. The CuInS2 films were determined to have a direct band gap of ca. 1.4 eV.

Ti(C,N) films have been deposited from tetrakis(dimethylamido)titanium (TDMAT) and ammonia by CVD at low pressure using pulsed Injection technique (ILPCVD). This procedure allows us to easily deposit Ti(C,N) films with a good reproducibility. It is an efficient technique to control growth rates and composition of coatings. The liquid TDMAT undergoes no degradation during deposition since it is kept at room temperature. Ti(C,N) films, with fee structure and fine grains were deposited at substrate temperature varying from 200 to 500 °C. Composition of films is controlled by substrate temperature and ammonia flow rate. Growth rates as high as 2 μm/min are reached for deposition of Ti(C,N) films at low temperature (350 °C).

A chemical solution powder synthesis technique has been developed that produces fine, uniform powders of lead magnesium niobate (PMN) with 60 to 80 nm crystallite size. The synthesis technique was based on the dissolution of lead acetate and alkoxide precursors in acetic acid followed by precipitation with oxalic acid/propanol solutions. Lead magnesium niobate ceramics fabricated from these chemically derived powders had smaller, more uniform grain size and higher dielectric constants than ceramics fabricated from mixed oxide powders that were processed under similar thermal conditions. Chem-prep PMN dielectrics with peak dielectric constants greater than 22,000 and polarizations in excess of 29 μC/cm2 were obtained for 1100°C firing treatments. Substantial decreases in dielectric constant and polarization were measured for chemically prepared PMN ceramics fired at lower temperatures, consistent with previous work on mixed oxide materials.

We have developed several solution-based preparations for nanocrystalline orthorhombic InS, which is a mid band gap semiconductor (2.44 eV) with potential applications in photovoltaics. Various reagents were used as indium (t-Bu3In, t-Bu2InCl) and sulfur (H2S, (TMS)2S) sources. Growth of crystalline powders was dependent upon the addition or in-situ generation of indium metal. These reactions represent the first reported use of a Solution-Liquid-Solid (SLS) mechanism by which semiconductors are grown from a molten metal flux for a system other than the III-V family of semiconductors. The studies on powder preparations were used to develop a new, low-temperature (185 °C) chemical-bath process for depositing a polycrystalline InS thin film. The film was deposited from a solution of t-Bu3In and elemental sulfur onto an indium-coated fused-silica substrate; the indium film acted as the crystallization medium.

The aim of this work was to develop a non-vacuum chemical deposition technique for YBa2Cu3O7-x (YBCO) coated conductors on rolling-assisted biaxially textured substrates (RABiTS). We have chosen the metal-organic decomposition (MOD) and sol-gel precursor routes to grow textured YBCO films. In the MOD process, yttrium 2-ethylhexonate, barium neodecanoate, copper 2-ethylhexonate and toluene were used as the starting reagents. YBCO films processed by the MOD method on SrTiO3 (100) single crystal substrates were predominately epitaxial and consisted of c and a-axis oriented material. Films have a TC,onset of 89K and the best superconducting transition temperature of 63K. Films pyrolyzed at 525 °C and subsequently annealed at 780 °C in P(O2) of 3.5 × 10−4 atm contained YBCO phase predominately in a-axis orientation. In the sol-gel route, yttrium-isopropoxide, barium metal, copper methoxide and 2-methoxyethanol were used as the starting reagents. Sol-gel YBCO films on SrTiO3 substrates were epitaxial and c-axis oriented.

The salt metathesis reaction between lead(II) salts and potassium chromate in methanolic solution, mediated by the formation of a soluble complex of potassium chromate with a cyclic polyether, affords orthorhombic PbCrO4 rather than the monoclinic modification formed in aqueous solution. When the aqueous metathesis reaction is carried out in the presence of tertiary amines, a lead oxide-rich phase, PbO•PbCrO4 (Pb2CrO5), is selectively formed.

Phosphate ceramics doped with Sm3+ and Tb3+ ions were synthesized through sol-gel process. Thin films of Tb3+ doped phosphosilicates were fabricated by spin coating of the phosphosilicate sols on SiOx/indium-tin-oxide/glass substrates. The gels synthesized by reaction of P2O5 with tetraethoxy silane (TEOS) were fired in air at a temperature range of 200°C – 900°C. The crystal structure was examined by x-ray diffractometry. Si5O(PO4)6 was the only crystalline phase. The fluorescence spectra of Sm3+ as a function of firing temperature, composition and structure of the matrices were investigated. The intensity of Sm3+ emission increased with increasing firing temperatures and greater proportion of phosphorus. The photocurrent of the films at 355 nm laser excitation was observed. The photoresponse as a function of laser energy was linear and showed no sign of saturation. The films exhibited stable photoresponse under a high number of laser shots.

The structures of four new tungsten based, ternary nitride compounds, Fe3W3N, Ni6W6N, Ni2W4N, and Fe4W2N, each prepared using a complexed precursor synthesis route, have been determined by Rietveld analyses of the respective powder x-ray diffraction (PXRD) data. Each compound crystallizes in a relatively complex cubic structure which is in general isostructural with the η-carbide structure. However, subtle structural differences which are compositionally dependent do exist between each nitride and these will be examined in detail in this paper.

A new alcohol solution based approach has been developed for preparing transition metal nitride thin films and coatings. In this technique, the metal of interest is dissolved as a chloride in acetonitrile, then chelated with triethanolamine to form a highly viscous solution which settles out of the solvent phase. The acetonitrile is then evaporated off and the remaining thick liquid precursor is easily diluted with water or methanol, yielding a semi-viscous liquid which can be used directly to coat various substrates. When heat treated under the appropriate conditions in ammonia, the precursor coating transforms to yield the corresponding nitride. This approach is currently being considered for preparing nitride-based thin film electrical components and has been successfully used thus far to spray deposit TaN and NbN nitride films onto silicon substrates. Results of the preliminary study on these two nitride films are discussed in this paper.

The process for generating films of Ba0.5Sr0.5TiO3, and PbZr0.48Ti0.52O3 by photochemical deposition from metal-organic thin films has been investigated. Films have also been prepared by metal-organic and sol-gel deposition for comparison with the photochemical method. All three methods could produce crystalline films of the target materials. Studies of the heating of the amorphous films prepared by each of the methods indicated that similar crystalline films could be prepared by the different methods. Under some conditions the photochemical methods gave the highest degree of orientation of the crystalline films.

Novel binary (Pb, Ti) coordination compound were synthesized and used as precursor for the preparation of PbTiO3 films by means of aerosol deposition and spin coating. Single-phased textured thin films of perovskite structure were fabricated on MgO(100) substrate at T=380°C.

Ferroelectric tead zirconate titanate, Pb(Zrx Tibx)O3 (hereafter abbreviated as PZT), thin films were prepared by annealing precursor films of multilayered structures composed of alternating layers of PZT aiKL lead titanate (hereafter abbreviated as PT). This method (which we refer to as multi-seeding) was used in order to lower the processing temperature of PZT. The precursor films were prepared from alkoxide precursor solutions. Effects of zirconium to titanium ratios and stacking structures of the multi-layered precursor films on crystallization behavior were studied to improve the electrical properties of the resultant PZT thin films. Layers of PT were inserted between every PZT layer in order to seed the crystallization of the desired perovskite phase. PT has previously been shown to crystallize with a pure perovskite structure at temperatures as low as 450 °C. Precursor layers of PZT with different compositions, ranging from x = 1 to x = 0.53 were prepared. In this process, the compositions of the PZT precursors and/or the stacking structure, as well as the heating schedule, had a large effect on the crystallization behavior. Nucleation control of the PT seeding layer by changing the heating schedules played an important role in preparing perovskite PZT thin films at low temperatures. Dielectric properties of the resultant films depended on the compositions and annealing temperatures. It was demonstrated that the composition of the resultant PZT film was controllable in the multi-seeding process, and that dielectric properties of the resultant films were improved.

Formation of ferrites from aqueous solution of metal salts is a well known process involving precipitation of metal hydroxides followed by oxidation of the resulting gel. The purpose of the present work was to determine the effects oxygen flow rate on the progress of the reaction and on the structure and properties of the resulting precipitate. The reaction was carried out at 70°C with pH of 10.5 and oxygen flow rate of 2,4, or 8 standard liters per hour. The progress of the reaction was monitored by following the oxidation-reduction potential of the solution, which changes dramatically after the Fe(II) is consumed. The reaction rate increased with increasing oxygen flow rate. The Mg content of the precipitate was lower than that of the reaction mixture, possibly because of the pH of the reaction mixture. X-ray diffraction and infrared spectroscopy confirmed formation of a ferrite under these conditions.

Potassium titanyl phosphate, KTiOPO4 (KTP), thin films were prepared by sol-gel process. The structural evolution of KTP thin films was investigated by means of DTA/TGA, XRD, and FT-IR. The electro-optical results show that KTP thin films have a refractive index of 1.8 and large quadratic electro-optical coefficient of R=2.50643*10−16 and have potential applications for electro-optical devices.

Cubic rare-earth aluminate perovskites of the general form REAIO3 have been identified as possible buffer layers for high current carrying cuprate superconductors deposited on roll-textured metals. This paper describes on-going research to develop solution routes which would avoid the use of slow and costly vacuum processing. Our research plan includes the development of an appropriate solution chemistry, studies of the crystallization behavior of powders under reducing and oxidizing conditions, deposition of polycrystalline films on silver substrates, deposition of epitaxial films on single-crystal oxide substrates, and deposition on roll textured nickel. The method is illustrated with the example of PrAlO3.

An all-alkoxide sol-gel process utilizing methoxyethoxide complexes in 2-methoxyethanol was used to prepare epitaxial films of SrBi2Nb2O9, SrBi2Ta2O9, BaBi2Nb2O9, BaBi2Ta2O9, and Bi4Ti3O12 on [100] oriented SrTiO3 single crystals. Films were prepared by spin coating strontium titanate substrates with partially hydrolyzed alkoxide solutions and firing in air at 850 °C for 20 minutes. Out-of-plane orientation was confirmed by θ-2θ scans which showed only [002ℓ] reflections. In-plane orientation was determined by pole figures and phi-scans about the [105] plane in the case of the (Sr,Ba)Bi2(Nb,Ta)2O9 complexes and the [117] plane in the case of Bi4Ti3O12. Lattice constants and full-width at half-maximum (fwhm) values for both in-plane and out-of-plane reflections are reported.

As integrated circuit sizes decrease below 0.25 microns, device performance will no longer improve at the same rate as for past generations because of RC interconnect delay which becomes significant as compared to the intrinsic gate delay. The parallel approaches to partially address this fundamental problem are to use a lower resistance metal (i.e., copper instead of aluminum) and to use a dielectric material with a dielectric constant significantly below that of dense silica (∼4). Recently, considerable progress has been made in development of thin films of nanoporous silica (also known as aerogels or low density xerogels) for these ILD and IMD applications. Advantages of these materials include high thermal stability, small pore size, and similarity to conventional spin-on deposition processes, spin-on glass precursors and final material (silica). The dielectric constant of nanoporous silica can be tailored between ∼1 and 3 which allows its’ implementation at multiple technology nodes in integrated circuit manufacture starting with the 0.18 micron node.

Research and development efforts at Nanoglass over the last several years have focused on; 1) simpler and more reproducible deposition processes, 2) a more complete understanding of processing-property relationships for this material, 3) scale-up of manufacturing to yield a range of precursor products with stability for at least six months and very high purity, and 4) working with customers to integrate this material into both aluminum/gapfill and copper/damascene process flows. Nanoglass has now developed a new process which considerably reduces the number of process steps and allows independent control of both film thickness and porosity. The current status of process and precursor development and device integration efforts for nanoporous silica is discussed.