Showing papers on "Chemical vapor deposition published in 1992"

Textured aluminum‐doped zinc oxide thin films from atmospheric pressure chemical‐vapor deposition

Abstract: Aluminum‐doped zinc oxide films have been deposited on soda lime glass substrates from diethyl zinc, triethyl aluminum, and ethanol by atmospheric pressure chemical‐vapor deposition in the temperature range 367–444 °C. Film roughness was controlled by the deposition temperature and the dopant concentration. The films have resistivities as low as 3.0 × 10−4 Ω cm, infrared reflectances close to 90%, visible transmissions of 85%, and visible absorptions of 5.0% for a sheet resistance of 4.0 Ω/⧠. The aluminum concentration within doped films measured by electron microprobe is between 0.3 and 1.2 at. %. The electron concentration determined from Hall coefficient measurements is between 2.0 × 1020 and 8.0 × 1020 cm−3, which is in agreement with the estimates from the plasma wavelength. The Hall mobility, obtained from the measured Hall coefficient and dc resistivity, is between 10.0 and 35.0 cm2/V s. Over 90% of the aluminum atoms in the film are electrically active as electron donors. Scanning electron microscopy and x‐ray diffraction show that the films are crystalline with disklike structures of diameter 100–1000 nm and height 30–60 nm. The films have the desired electrical and optical properties for applications in solar cell technology and energy efficient windows.

Characterization of bias-enhanced nucleation of diamond on silicon by invacuo surface analysis and transmission electron microscopy.

Abstract: An in-depth study has been performed of the nucleation of diamond on silicon by bias-enhanced microwave plasma chemical vapor deposition. Substrates were pretreated by negative biasing in a 2% methane-hydrogen plasma. The bias pretreatment enhanced the nucleation density on unscratched silicon wafers up to ${10}^{11}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ as compared with ${10}^{7}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ on scratched wafers. In vacuo surface analysis including x-ray photoelecton spectroscopy (XPS), Auger electron spectroscopy, and combined XPS and electron-energy-loss spectroscopy were used to study systematically both the initial-nucleation and growth processes. High-resolution cross-sectional transmission electron microscopy (TEM) was used to study the physical and structural characteristics of the diamond-silicon interface as well as to complement and enhance the in vacuo surface-analytical results. Raman spectroscopy confirmed that diamond was actually nucleating during the bias pretreatment. Scanning electron microscopy has shown that once the bias is turned off, and conventional growth is conducted, diamond grows on the existing nuclei and no continued nucleation occurs. If the bias is left on throughout the entire deposition, the resulting film will be of much poorer quality than if the bias had been turned off and conventional growth allowed to begin. Intermittent surface analysis showed that a complete silicon carbide layer developed before diamond could be detected. High-resolution cross-sectional TEM confirmed that the interfacial layer was amorphous and varied in thickness from 10 to 100 \AA{}. A small amount of amorphous carbon is detected on the surface of the silicon carbide and it is believed to play a major role in the nucleation sequence. A model is proposed to help explain bias-enhanced nucleation on silicon, in hopes that this will improve the understanding of diamond nucleation, in general, and eventually result in the nucleation and growth of better-quality diamond films.

Textured diamond growth on (100) β‐SiC via microwave plasma chemical vapor deposition

Abstract: Textured diamond films have been deposited on β‐SiC via microwave plasma chemical vapor deposition preceded by an in situ bias pretreatment that enhances nucleation. Approximately 50% of the initial diamond nuclei appear to be aligned with the C(001) planes parallel to the SiC(001), and C[110] directions parallel to the SiC[110] within 3°. The diamond was characterized by Raman spectroscopy and scanning electron microscopy.

Atmospheric pressure chemical vapor deposition of gallium doped zinc oxide thin films from diethyl zinc, water, and triethyl gallium

Abstract: Gallium doped zinc oxide films have been deposited in the temperature range 150 to 470 °C from 0.05% diethyl zinc, 0.8% water, and various triethyl gallium concentrations. The films are polycrystalline with crystallite sizes varying between 275 and 500 A for undoped films and between 125 and 400 A for doped films. Only those films deposited above 430 °C are highly oriented and have their c axes perpendicular to the substrate plane. The electron density, conductivity, and mobility always increase with temperature. Thicker films have higher conductivity and mobility than thinner films. The refractive index is reduced from 1.96 to 1.73 when the electron density is increased from zero to 3.7×1020 cm−3. For films deposited at 370 °C with a gallium concentration of about 2.5 at. %, the ratio of conductivity to visible absorption coefficient increases from 0.03 to 1.25 Ω−1 when the film thickness increases from 0.11 to 1.2 μm. A film deposited at 470 °C with a gallium concentration of 2.4 at. % and a thickness o...

Hydride vapor phase epitaxial growth of a high quality GaN film using a ZnO buffer layer

Abstract: In hydride vapor phase epitaxial (HVPE) growth of GaN, the sputtered ZnO layer has been found to be one of the best buffer layers because of the fact that physical properties of ZnO are nearly analogous with those of GaN. With a ZnO buffer layer, the reproducibility of growing GaN single crystal by HVPE has been greatly improved. The GaN films grown by this method show excellent crystalline, electrical, and optical properties. In particular, the Hall mobility of 1920 cm2 V−1 s−1 at 120 K is the highest value that has ever been reported by HVPE.

Method and apparatus for low temperature, low pressure chemical vapor deposition of epitaxial silicon layers

Abstract: A method and apparatus for depositing single crystal, epitaxial films of silicon on a plurality of substrates in a hot wall, isothermal deposition system is described. The deposition temperatures are less than about 800° C., and the operating pressures during deposition are such that non-equilibrium growth kinetics determine the deposition of the silicon films. An isothermal bath gas of silicon is produced allowing uniform deposition of epitaxial silicon films simultaneously on multiple substrates. This is a flow system in which means are provided for establishing an ultrahigh vacuum in the range of about 10-9 Torr prior to epitaxial deposition. The epitaxial silicon layers can be doped in-situ to provide very abruptly defined regions of either n- or p-type conductivity.

Ti-Si-N films prepared by plasma-enhanced chemical vapor deposition

Abstract: Ti-Si-N thin films were deposited on HSS substrates at 560°C using plasmaenhanced chemical vapor deposition. Feed gases used were TiCl4, SiCl4, N2, and H2. The composition of the films could be controlled well through adjustment of the mixing ratio of the chlorides in the feed gases. The Si content in the film varied in the range of O to 40 at. %. It was jbund that a small addition of Si to a TiN film improved the morphology significantlv, showing dense and glasslike structure. Also a much smootherand more homogeneous interface between thefilm and the substrate was obtained. The Ti-Si- N films containing 10–15 at. % Si showed the maximal microhardness value of about 6350 kgf/mm2, much higher than that of TiN films.

Chemical vapor deposition method for forming fluorine containing silicon oxide film

Abstract: A chemical vapor deposition method for forming a fluorine-containing silicon oxide film comprises introducing a gaseous mixture of alkoxysilane or its polymers as a source gas with fluoroalkoxysilane added thereto into a reaction chamber and performing decomposition of the gaseous mixture to deposit the fluorine-containing silicon oxide film onto a substrate. During the formation of the fluorine-containing silicon oxide film, at least one of compounds containing phosphorus or boron such as organic phosphorus compounds and organic boron compounds may be evaporated and introduced into said gaseous mixture, thereby adding at least one of phosphorus and boron to said fluorine-containing silicon oxide film. The fluorine-containing oxide film may be formed by effecting the decomposition of the gaseous mixture in the presence of ozone gas, or under ultraviolet radiation, or gas plasma.

Surface science at atmospheric pressure: Reconstructions on (001) GaAs in organometallic chemical vapor deposition

Abstract: We report the first observation of reconstructions on semiconductor surfaces in atmospheric pressure (AP) environments. Using reflectance-difference spectroscopy we show that the primary reconstructions that occur on (001) GaAs in ultrahigh vacuum (UHV) also occur under AP H 2 , He, and N 2 . These results demonstrate that dimer formation is not restricted to surfaces in UHV and justify the use of UHV studies to determine (001) GaAs chemistry during AP organometallic chemical vapor deposition (OMCVD)

A PROCESS FOR DEPOSITING A SIOx FILM HAVING REDUCED INTRINSIC STRESS AND/OR REDUCED HYDROGEN CONTENT

Abstract: A process for reducing intrinsic stress and/or hydrogen content of a SiOx film grown by chemical vapor deposition. The process is applicable to plasma-enhanced and electron cyclotron resonance chemical vapor deposition of silicon dioxide wherein a vapor phase etchant is introduced while growing the silicon dioxide film. The presence of the etchant during the plasma deposition process allows for selective removal of high energy silicon dioxide molecules in the growing film thus reducing intrinsic stress within the film. The use of halogen etchants further reduces the amount of hydrogen present as hydroxyl within the film.

Single‐crystalline, epitaxial cubic SiC films grown on (100) Si at 750 °C by chemical vapor deposition

Abstract: Single‐crystalline, epitaxial cubic (100) SiC films have been grown on (100) Si substrates at 750 °C by low‐pressure chemical vapor deposition, using methylsilane, SiCH3H3, a single precursor with a Si:C ratio of 1:1, and H2. This epitaxial growth temperature is the lowest reported to date. The films were characterized by means of transmission electron microscopy, x‐ray diffraction, infrared transmission, four‐point probe and other methods. Based on double‐crystal x‐ray diffractometry, the crystalline quality of our films is equivalent to that of commercial films of similar thickness. The letter describes the novel growth apparatus used and the properties of the films.

Characterization of boron carbide thin films fabricated by plasma enhanced chemical vapor deposition from boranes

Abstract: We have fabricated boron carbide thin films on Si(111) and other substrates by plasma‐enhanced chemical‐vapor deposition (PECVD). The PECVD of boron carbides from nido‐cage boranes, specially nido‐pentaborane(9) (B5H9), and methane (CH4) is demonstrated. The band gap is closely correlated with the boron to carbon ratio and can range from 0.77 to 1.80 eV and is consistent with the thermal activation barrier of 1.25 eV for conductivity. We have made boron carbide by PECVD from pentaborane and methane that is sufficiently isotropic to obtain resistivities as large as 1010 Ω cm at room temperature. This material is also shown to be suitable for photoactive p‐n heterojunction diode fabrication in combination with Si(111).

Unusually high thermal conductivity in diamond films

Abstract: Chemical‐vapor‐deposited (CVD) polycrystalline diamond films have recently been reported with a thermal conductivity that is only 25% less than that of high quality single‐crystal natural diamond. By studying a series of such films of various thicknesses grown under virtually identical conditions, we have discovered a significant (factor of four) through the thickness gradient in thermal conductivity. The observed gradient is attributed mainly to phonon scattering by the roughly cone‐shaped columnar microstructure. For 350 μm films, the material near the top (growth) surface has a conductivity of at least 21 W/cm °C, i.e., comparable to the best single crystals. This remarkable dependence of thermal conductivity on microstructure has important implications for thermal management of microelectronic devices using CVD diamond.

Frequency effects in silane plasmas for plasma enhanced chemical vapor deposition

Abstract: It is now generally recognized that the excitation frequency is an important parameter in radio‐frequency (rf) plasma‐assisted deposition. Very‐high‐frequency (VHF) silane plasmas (50–100 MHz) have been shown to produce high quality amorphous silicon films up to 20 A/s [H. Curtins, N. Wyrsch, M. Favre, and A. V. Shah, Plasma Chem. Plasma Processing 7, 267 (1987)], and therefore the aim of this work is to compare the VHF range with the 13.56 MHz industrial frequency in the same reactor. The principal diagnostics used are electrical measurements and a charge coupled device camera for spatially resolved plasma‐induced emission with Abel inversion of the plasma image. We present a comparative study of key discharge parameters such as deposition rates, plasma uniformity, ion impact energy, power transfer efficiency, and powder formation for the rf range 13–70 MHz.

Deposition mechanism of hydrogenated hard‐carbon films in a CH4 rf discharge plasma

Abstract: To examine the mechanism of film deposition in a planar rf CH4 discharge plasma, measurements were made of the spatial distributions of the deposition rate and optical emission intensity along the discharge axis between parallel electrodes. Optical‐absorption properties of the deposited carbon films were also measured over both the infrared and visible regions. To measure the spatial deposition rates, the substrate surface was elevated from the cathode electrode with the use of quartz glass plates. It was found that the spatial properties of films, which were deposited in both the ion‐sheath and bulk‐plasma regions, differ markedly from each other. The carbon films obtained from within the ion‐sheath region were found to be extremely hard, while those obtained in the bulk‐plasma region were polymerlike soft films. This disparity was thought to be due to the difference in the kinetic energy of the ions bombarding the substrate surface; that is, the substrate surface potential could be changed by elevating the substrate surface. These results were incorporated in the discussion of the deposition mechanism, with emphasis on the contribution of ion bombardment to the film‐deposition process. It was tentatively concluded that the film‐deposition rate was predominantly dependent on the product of the ion kinetic energy and ion flux density that reached the substrate surface.

Low‐temperature conductivity of ZnO films prepared by chemical vapor deposition

Abstract: c‐axis‐oriented ZnO films were prepared in O2 atmosphere by chemical vapor deposition using zinc acetylacetonate for source material. A minimum value of resistivity, 2.44 Ω cm, was obtained at a film formation temperature of 550 °C. The resistivity of the films was measured at low temperatures (87–297 K). For temperatures between 200 and 297 K band conduction included boundary scattering due to both thermionic emission and thermal‐field emission at the grain‐boundary barriers in the films, and the activation energy obtained ranged from 1.45 to 6.32×10−2 eV. For temperatures lower than about 200 K, the conductivity deviated from linear Arrhenius plots suggesting variable range‐hopping conduction. Discussions based on assumed electron mobility and concentration lead to variable range‐hopping conduction by localization of electrons in impurity levels in the intermediate concentration region. Mott’s parameters in the variable range‐hopping conduction were estimated for the films.

Epitaxial growth of BaTiO3 thin films by organometallic chemical vapor deposition

Abstract: Epitaxial BaTiO3 thin films were grown in situ on (100) LaAlO3 by low‐pressure organometallic chemical vapor deposition using the precursors Ba (hexafluoroacetylacetonate)2 (tetraglyme) and titanium tetraisopropoxide. The phase composition and epitaxial quality were sensitive to the reactant partial pressures and growth temperature. Deposition at 800 °C yielded [100]‐oriented BaTiO3 films. In‐plane epitaxy was confirmed for the BaTiO3 films by x‐ray diffraction.

Filtered arc deposition of amorphous diamond

Abstract: A cathodic arc with beam filter is employed for the deposition of hydrogen‐free amorphous carbon films. A linear filter is used to prevent macroparticles and nonionized carbon atoms from reaching the substrate. The deposited films are characterized by their optical and mechanical behavior. Depending on the deposition conditions, optical band gaps in the range 2.1–2.4 eV are measured. Mechanical properties are investigated using the nanoindentation method and are shown to approach those of natural diamond. To our knowledge, the data obtained thus far reveal these films to be more diamondlike than those prepared using any other method for the deposition of nonhydrogenated amorphous diamond.

Low‐temperature preparation of SiO2/Si(100) interfaces using a two‐step remote plasma‐assisted oxidation‐deposition process

Abstract: SiO2/Si(100) interfaces have been prepared by a low‐temperature, 200–300 °C, remote plasma‐assisted oxidation‐deposition process. The oxidation: (i) creates ∼0.5 nm of SiO2; (ii) removes residual C from an otherwise H‐terminated Si surface; and (iii) produces a SiO2/Si interface with a midgap trap density of ∼1×1010 cm−2 eV−1, and when combined with remote plasma‐enhanced chemical vapor deposition (RPECVD) of SiO2, (iv) forms a SiO2/Si structure with properties comparable to those prepared by thermal oxidation of Si at 850–1050 °C.

Microhardness and Young’s modulus of diamond and diamondlike carbon films

Abstract: The microhardness, H, and Young’s modulus, E, of a polycrystalline diamond film and several amorphous diamondlike carbon (DLC) films were determined from force‐displacement curves obtained using an ultralow‐load microhardness instrument (UMIS‐2000). Measurements were made at a constant loading rate of 3 mN/s, to a maximum applied force of 67 and 100 mN with contact force of 0.06 and 1.07 mN, respectively. The diamond film had a surface morphology typical of microwave plasma chemical vapor deposition films (crystallite size 0.5–3 μm), and the force‐displacement curves showed nearly complete elastic behavior. The average values of hardness (80–100 GPa) and modulus (500–533 GPa) are comparable to those of natural (001) diamond reference standards (H=56–102 GPa, E=1050 GPa). The DLC films were prepared by low‐energy ion‐assisted unbalanced magnetron sputtering. By varying the bombarding ion energy, five films were prepared having different sp3/sp2 bonding ratios (3–6), optical gaps (1.2–1.6 eV), and hydrogen ...

Metal alkoxides and β-diketonates as precursors for oxide and non-oxide thin films

Abstract: Single-components or multicomponent oxide thin films are of interest for electronic and opto-electronic devices, optical applications, catalysis, corrosion protection etc Their preparation by chemical routes is based on the hydrolytic (sol-gel process) or pyrolytic (MOCVD) conversion of precursors Derivatives having MO bonds, namely metal alkoxides, carboxylates or β-diketonates, are the most common sources of metal oxides The properties of alkoxides are appropriate for sol-gel as well as MOCVD applications, whilst the limited hydrolytic susceptibility but good volatility of β-diketonates is most convenient for MOCVD purposes The low temperature and flexibility of sol-gel routes, and the presence of residual OH groups in the final films, are favorable for the encapsulation of organic or organometallic derivatives, the anchoring of enzymes and in general for the development of functional and composite coatings The facile formation of heterometallic alkoxides is also attractive for the development of coatings based on multimetallic formulations MOCVD is favorable for the buildup of heterostructures and epitaxial layers Although metal alkoxides and β-diketonates are usually oxide precursors, nitride or sulfide films can be obtained by reacting with the appropriate reagents Fluorinated ligands enhance volatility but often result in the formation of metal fluorides

Growth kinetics of (100), (110), and (111) homoepitaxial diamond films

Abstract: We present the first investigation of the growth kinetics of diamond films grown homoepitaxially by hot‐filament chemical vapor deposition on (100), (110), and (111) natural diamond substrates. Growth rates on the various faces exhibited different functional dependencies on CH4 flow rate, being linear on (100), slightly sublinear on (110), and sigmoidal on (111). The temperature dependence of the growth rate was also crystal‐face‐dependent, yielding effective activation energies of 8±3, 18±2, and 12±4 kcal/mol for [100], [110], and [111] growth, respectively, at substrate temperatures between 735 and 970 °C. The apparent activation energies were considerably larger at substrate temperatures between 675 and 735 °C. We propose that these crystal face and temperature effects are due principally to differences and changes in the nanometer‐scale morphology and surface hydrogen coverage with methane concentration and surface temperature.

Pulsed gas plasma-enhanced chemical vapor deposition of silicon

Abstract: A substrate having silicon receptive surface areas is maintained in a plasma enhanced chemical vapor deposition (PECVD) chamber at a temperature, and under sufficient gas flow, pressure and applied energy conditions to form a gas plasma. The gas plasma is typically made up of hydrogen, but may be made up of mixtures of hydrogen with other gasses. A discontinuous flow of silane gas of predetermined duration and predetermined time spacing is introduced to produce at least one timed pulse of silane gas containing plasma, whereby a thin layer of silicon is deposited on the receptive areas of the substrate. The thin layer of silicon is exposed to the hydrogen gas plasma between the brief deposition time cycles and may result in the modification of the silicon layer by the hydrogen plasma. The surface modification may include at least one of etching, surface hydrogenation, surface bond reconstruction, bond strain relaxation, and crystallization, and serves the purpose of improving the silicon film for use in, for example, electronic devices. Repeated time pulses of silane gas and subsequent hydrogen plasma exposure cycles can result in selective deposition of silicon on predetermined receptive areas of a patterned substrate. Selective deposition of silicon can serve the purpose of simplifying electronic device manufacturing, such as, for example, the fabrication of amorphous silicon thin film transistors with low contact resistance in a single PECVD pump-down procedure.

A single-source precursor to titanium nitride thin films. Evidence for the intermediacy of imido complexes in the chemical vapor deposition process

Abstract: Monomeric titanium and zirconium complexes with multiple bonds to oxygen, sulfur, and nitrogen have attracted considerable attention due to their novel structural features and interesting reactivity. Recently, we have initiated a research program that is designed to prepare models for complexes involved in chemical vapor deposition (CVD) processes of early transition metal materials. Species containing metal-element multiple bonds have featured prominently in mechanistic conjecture about CVD reactions, although little hard evidence is available to back up such speculation. It was disclosed that excellent-quality thin films of titanium nitride can be prepared by the atmospheric pressure CVD reaction of titanium tetrachloride with alkylamines at temperatures between 350 and 600 {degrees}C. This process appeared ideal for detailed mechanistic scrutiny, since titanium tetrachloride is well-known to be highly reactive toward amines{sup 9} and because titanium should be capable of stabilizing a variety of nitrogen ligand types. In this context, we report the synthesis and characterization of two complexes that are formed in the solution-phase reactions of titanium tetrachloride with tert-butylamine. To the best of our knowledge, the first of these, a chloride-amide-amine complex, comprises the first single-source CVD precursor to high-quality gold-colored films of titanium nitride. Additionally, a monomeric imido complex has beenmore » trapped with triphenyl-phosphine oxide and has been structurally characterized. Evidence is presented from mass spectrometry for the intermediacy of imido complexes in the CVD process. The present results provide partial mechanistic insight into the sequence that leads from titanium tetrachloride and tert-butyl-amine to titanium nitride thin films. The system implies that imido complexes play an important role in other film forming processes.« less

Performance of thin-film transistors on polysilicon films grown by low-pressure chemical vapor deposition at various pressures

Abstract: Defect properties of undoped low-pressure chemical-vapor-deposited (LPCVD) polysilicon films have been investigated by capacitance techniques on a simple metal-oxide-semiconductor (MOS) capacitor structure. The results show that the effective density of bulk and interface trap states is almost independent of the deposition pressure. After reducing the polysilicon film thickness by etching, although the grain size decreases due to the columnar mode of growth at low pressures, the trap states density reduces significantly. This finding could be explained by the hypothesis that, during the growth of the material, impurities are segregated at the film surface by fast diffusion through the grain boundaries. The transport properties of 0.5- mu m-thick polysilicon films deposited at a pressure ranging from 100 to 0.5 mtorr were evaluated from measurements on thin-film transistors (TFTs). The results demonstrate that at high pressures the grain boundaries and at low pressures the polysilicon-SiO/sub 2/ interface roughness scattering are the main factors in determining the transistor performance. >

Simulation of the gas‐phase processes in remote‐plasma‐activated chemical‐vapor deposition of silicon dielectrics using rare gas–silane‐ammonia mixtures

Abstract: Remote‐plasma‐activated chemical‐vapor deposition (RPACVD) is a method whereby thin films are deposited with the substrate located out of the plasma zone. The lower rate of energetic ion and photon bombardment in RPACVD compared to conventional direct‐plasma‐enhanced chemical‐vapor deposition (DPECVD) reduces damage to the substrate. The use of RPACVD also enables one to more carefully tailor the flux of radicals to the substrate compared to DPECVD. This selectivity results from both physically isolating the substrate from undesirable radicals and limiting the variety of chemical pathways that produce radicals. A model for RPACVD is described and results from the model are discussed in the context of comparing gas mixtures and geometries in which this selectivity may be achieved. The chemistries investigated are Rg/SiH4 (Rg=Ar, He) for deposition of Si and Rg/NH3/SiH4 (Rg=Ar, He) for deposition of Si3N4. It is found that the selectivity in producing radicals that can be obtained by excitation transfer from excited states of rare gases is easily compromised by reactor configurations that allow injected gases to penetrate into the plasma zone.

Atomic layer epitaxy of GaN over sapphire using switched metalorganic chemical vapor deposition

Abstract: In this letter we report the first switched atomic layer epitaxy (SALE) of single crystal GaN over basal plane sapphire substrates. A low pressure metalorganic chemical vapor deposition (LPMOCVD) system was used for the epilayer depositions. In contrast to conventional LPMOCVD requiring temperatures higher than 700 °C, the SALE process resulted in single crystal insulating GaN layers at growth temperatures ranging from 900 to 450 °C. The band‐edge transmission and the photoluminescence of the films from the SALE process were comparable to the best LPMOCVD films. To the best of our knowledge this is the first report of insulating GaN films which show excellent band‐edge photoluminescence.

Structural and electrical studies on rapid thermally processed ferroelectric Bi4Ti3O12 thin films by metallo‐organic solution deposition

Abstract: Thin films of Bi4Ti3O12 that were pinhole free with uniform composition and thickness were prepared by the metallo‐organic solution deposition technique on platinum coated silicon and bare silicon substrates. Crack free and crystalline films of 5000 A thickness were fabricated by spinning and post deposition rapid thermal annealing treatment at 500 °C. The films exhibited good structural, dielectric, and ferroelectric properties. The effects of annealing temperature and time on the structural and electrical properties of the films were evaluated. The measured small signal dielectric constant and dissipation factor at a frequency of 100 kHz were 184 and 0.039, respectively for a film rapid thermally annealed at 700 °C for a time of 10 s. Room temperature resistivity of 108 Ω cm and leakage current density of less than 10−7 A/cm2 were obtained for a 0.5‐μm‐thick film at an applied electric field of 100 kV/cm; establishing good insulating behavior. Ferroelectricity was confirmed by P–E hysteresis loops with ...

Temperature and concentration distribution of H2 and H atoms in hot-filament chemical-vapor deposition of diamond

Abstract: The temperature and concentration distributions of hydrogen in a hot‐filament chemical‐vapor deposition reactor of diamond have been measured simultaneously by coherent anti‐Stokes Raman scattering (CARS). The bright background from the filament was rejected by using CARS and gating on the detector as well as spatial filtering. The CARS spectra provided direct and accurate measurements of the H2 temperature and concentration distributions. The concentration distribution of atomic hydrogen was also determined by assuming a constant pressure condition and equilibrium between translational and rotational degrees of freedom in the system. These temperature and concentration distributions are essential for the understanding and modeling of the diamond growth processes. It was found that the H‐atom distribution departed substantially from the thermal equilibrium prediction except very near the filament; however, a diffusion‐controlled model predicted the slope of this distribution throughout the measured region.