Showing papers on "Pulsed laser deposition published in 1994"

Pulsed laser deposition of thin films

Abstract: Partial table of contents: History and Fundamentals of Pulsed Laser Deposition (J. Cheung). Diagnostics and Characteristics of Laser--Produced Plasmas (D. Geohegan). Particulates Generated by Pulsed Laser Ablation (L.--C. Chen). Angular Distribution of Ablated Material (K. Saenger). Film Nucleation and Film Growth in Pulsed Laser Deposition of Ceramics (J. Horwitz & J. Sprague). Processes Characteristics and Film Properties in Pulsed Laser Plasma Deposition (S. Metev). Commercial Scale--Up of Pulsed Laser Deposition (J. Greer). Pulsed Laser Deposition: Future Trends (T. Venkatesan). Comparison of Vacuum Deposition Techniques (G. Hubler). Pulsed Laser Deposition of High--Temperature Superconducting Thin Films for Active and Passive Device Applications (R. Muenchausen & X. Wu). Pulsed Laser Deposition of Metals (J. Kools). Appendix. References. Index.

Thin-Film Deposition: Principles and Practice

Abstract: Thin Film Technology. Gas Kinetics. Vacuum Technology. Evaporation. Deposition. Epitaxy. Chemical Vapor Deposition. High-Energy Techniques. Plasma Processes. Film Characterization.

Handbook of deposition technologies for films and coatings

Abstract: Deposition Technologies: An Overview * Plasmas in Deposition Processes * Surface Preparation For Film and Coating Deposition Processes * Evaporation: Processes, Bulk Microstructures And Mechanical Processes * Sputter Deposition Processes * Ion Plating * Chemical Vapor Deposition * Plasma-Enhanced Chemical Vapor Deposition * Plasma-Assisted Vapor Deposition Processes: Overview * Deposition from Aqueous Solutions: An Overview * Advanced Thermal Spray Deposition Techniques * Non-Elemental Characterization of Films and Coatings * Film Growth and Structure of PVD Deposits * Metallurgical Applications * Characterization of Thin Films And Coatings.

Formation of artificial batio3/srtio3 superlattices using pulsed laser deposition and their dielectric properties

Abstract: We have formed strained dielectric superlattices of BaTiO3 (BTO) and SrTiO3 (STO) by a pulsed laser deposition technique. A large strain of 400–500 MPa is introduced at the interface between the BTO and STO layers. A large dielectric constant of 900 was observed with a stacking periodicity of 2 unit cells/2 unit cells. The superlattices show drastically different electrical behavior from that of the solid solution (Sr,Ba)TiO3 films. Broad maxima of the dielectric constants occur around 40–50 °C and the values remain large even for a temperature above 200 °C.

Characteristics of high quality ZnO thin films deposited by pulsed laser deposition

Abstract: This paper show that under optimized deposition condition, films can be grown having a full width at half maximum (FWHM) value of the (002) x-ray diffraction (XRD) line a factor of 4 smaller than the previously published results using PLD and among the best reported so far by any technique. Under optimized conditions, c-axis oriented ZnO films having a FWHM value of the (002) XRD reflection line less than 15°, electrical resistivities around 5 × 10-2 Ω cm and optical transmittance higher than 85% in the visible region of the spectrum were obtained. Refractive index was around 1.98 and the Eg = 3.26 eV, values characteristic of very high quality ZnO thin films.

Pulsed laser deposition of VO2 thin films

Abstract: High quality vanadium dioxide (VO2) thin films have been successfully deposited by pulsed laser deposition without postannealing on (0001) and (1010) sapphire substrates. X‐ray diffraction reveals that the films are highly oriented with (010) planes parallel to the surface of the substrate. VO2 thin films on (0001) and (1010) substrates show semiconductor to metal transistions with electrical resistance changes as large as 4×104, 105, respectively. Thin films on (1010) substrate have a transition at as low as 55 °C with a hysteresis less than 1 °C. These transition properties are comparable with single crystal VO2.

Ion-assisted pulsed laser deposition of cubic boron nitride films

Abstract: Ion‐assisted pulsed laser deposition has been used to produce films containing ≳85% sp3‐bonded cubic boron nitride (c‐BN) By ablating from a target of hexagonal boron nitride (h‐BN), BN films have been deposited on heated (50–800 °C) Si(100) surfaces The growing films are irradiated with ions from a broad beam ion source operated with Ar and N2 source gasses Successful c‐BN synthesis has been confirmed by Fourier transform infrared (FTIR) spectroscopy, high‐resolution transmission electron microscopy (TEM), selected‐area electron diffraction, electron energy‐loss spectroscopy, and x‐ray diffraction The films are polycrystalline and show grain sizes up to 300 A In addition, Rutherford backscattering, elastic recoil detection, and Auger electron spectroscopies have been used to further characterize the samples The effects of varying ion current density, substrate growth temperature, growth time, and ion energy have been investigated It is found that stoichiometric films with a high c‐BN percentage ca

On the role of ions in the formation of cubic boron nitride films by ion-assisted deposition

Abstract: We have investigated how ion irradiation can selectively promote the formation of dense sp3-bonded cubic boron nitride (cBN) over the graphite-like sp2-bonded phases. We have conducted a series of experiments using ion-assisted pulsed laser deposition in which either the ion mass (mion) or ion energy (E) was varied in conjunction with the ratio of ion flux to depositing atom flux (J/a). For a fixed ion energy and mass, there is a critical J/a above which cBN formation is initiated, a window of J/a values in which large cBN percentages are obtained, and a point at which J/a is so large that the resputter and deposition rates balance and there is no net film deposition, in agreement with Kester and Messier. As do Kester and Messier, we find that cBN formation is controlled by a combination of experimental parameters that scale with the momentum of the ions. However, unlike Kester and Messier, we do not find that cBN formation scales with the maximum momentum that can be transferred in a single binary collision, as either incorrectly formulated by Targove and Macleod and used by Kester and Messier, or as correctly formulated. Instead we observe that cBN formation best scales with the total momentum of the incident ions, (mionE)1/2. We also consider the mechanistic origins of this (mionE)1/2 dependence. Computer simulations of the interaction of ions with BN show that cBN formation cannot be simply scaled to parameters such as the number of atomic displacements or the number of vacancies produced by the ion irradiation. A critical examination of the literature shows that none of the proposed models satisfactorily accounts for the observed (mionE)1/2 dependence. We present a quantitative model that describes the generation of stress during ion-assisted film growth. The model invokes a kinetic approach to defect production and loss. We apply a simplified version of the model to cBN synthesis, and find that it predicts an approximate (mionE)1/2 dependence for cBN formation.

Control of electrical conductivity in laser deposited SrTiO3 thin films with Nb doping

Abstract: Nb‐doped SrTiO3 (STO) thin films (Nb, 0

Triangular deposition chamber for a vapor deposition system

Abstract: A process and apparatus for the manufacture of chemical vapor deposited silicon carbide which comprises conveying the reaction gases to a triangular chemical vapor deposition cell where material is deposited by chemical vapor deposition. The triangular cell provides a large surface area for deposition while occupying a minimum amount of the furnace floor surface area. The triangular cell has the added benefit in that deposited silicon carbide is of negligible thickness at the edges thereby permitting easy separation of material with a minimum of post deposition machining.

Transparent conducting thin films of GaInO3

Abstract: GaInO3 is recently identified transparent conducting material which is structurally and chemically distinct from indium tin oxide [R. J. Cava, J. M. Phillips, J. Kwo, G. A. Thomas, R. B. van Dover, S. A. Carter, J. J. Krajewski, W. F. Peck, Jr., J. H. Marshall, and D. H. Rapkine, Appl. Phys. Lett. 64, 2071 (1994)]. We have used both dc reactive sputtering in the on‐ and off‐axis geometries and pulsed laser deposition to grow films of this material. Layers of pure GaInO3 as well as those partially substituted with Ge for Ga or Sn for In have been studied. Both growth techniques are capable of producing films with conductivity ∼400 (Ω cm)−1 and transmission as high as 90% throughout the visible spectrum for ∼1‐μm‐thick films. The growth techniques differ in the morphology of the films produced as well as in the degree of dopant incorporation that can be achieved. A post‐growth anneal in H2 can help produce an optimized oxygen content and a reduction of resistivity. Hall measurements indicate a carrier conce...

The magnetic and structural properties of pulsed laser deposited epitaxial MnZn–ferrite films

Abstract: The magnetic and structural properties of pulsed laser deposited MnZn–ferrite films have been examined. The results show that the uniaxial anisotropy, ferromagnetic resonance linewidth and coercive force are strongly influenced by the microstructure of the films, and the saturation magnetization and first‐order magnetocrystalline anisotropy constant depend on intrinsic properties such as composition and cation site occupation. A comparison of bulk and film magnetic properties shows that the magnetic properties of the films are comparable to the bulk, which makes pulsed laser deposition ferrite films a prime candidate for thin film high‐frequency microwave device applications.

Growth of epitaxial strontium barium niobate thin films by pulsed laser deposition

Abstract: We report the growth of epitaxial SrxBa1−xNb2O6 (SBN) thin films by pulsed laser deposition. The films were grown on (100) MgO substrates with thicknesses in the range 200–400 nm. Rutherford backscattering analysis showed that the films have stoichiometric composition identical to the target material. X‐ray diffraction 2θ scans indicate single crystalline layers with the (001) orientation perpendicular to the substrate plane. Phi scans on the (221) plane, however, reveal that the films have two in‐plane orientations. The unit cell of SBN is rotated in the plane of the film by ±18.4° with respect to the MgO substrate unit cell. This rotation is explained using a model which takes into account both the lattice match and the electrostatic energy within the heteroepitaxial interface.

Oxide superconductor and magnetic metal thin film deposition by pulsed laser ablation: a review

Abstract: A practical review of the use of laser ablation for the deposition of thin films of oxide superconductors and metals is presented. Details of the design and operation of a laser ablation deposition system are discussed, together with the influence of operating parameters such as laser wavelength and power density on the film growth, with the aim of assisting the researcher beginning to use and/or study laser ablation deposition.

Ferromagnetic La0.6Pb0.4MnO3 thin films with giant magnetoresistance at 300 K

Abstract: Highly textured, as-deposited $La_{0.6}Pb_{0.4}MnO_3$ thin films have been grown on $LaAlO_3$ by pulsed laser deposition. The films are ferromagnetic metals below 300 K. Giant negative magnetoresistance of over 40% is observed at 300 K at 6 T.

Microstructure of cubic boron nitride thin films grown by ion-assisted pulsed laser deposition

Abstract: A microstructural study of boron nitride films grown by ion‐assisted pulsed laser deposition is presented Fourier transform infrared spectroscopy, electron‐energy‐loss spectroscopy, and electron‐diffraction measurements indicate that within the ion‐irradiated region on the substrate, the film consists of a high fraction of the cubic phase (cBN) with a small amount of the turbostratic phase; outside the irradiated region, only the turbostratic phase is detected Conventional and high‐resolution electron microscopic observations show that the cBN is in the form of twinned crystallites, up to 40 nm in diameter Particulates, formed by the laser ablation process, reduce the yield of cBN in the irradiated regions by shadowing local areas from the ion beam The films exhibit a layered structure with an approximately 30‐nm‐thick layer of oriented turbostratic material forming initially at the silicon substrate followed by the cBN The observations of oriented turbostratic material and twinned cBN crystallites a

Growth of KNbO3 thin films on MgO by pulsed laser deposition

Abstract: KNbO3 crystals have numerous uses in electro-optical, nonlinear optical, and photorefractive device applications. However, their widespread availability is somewhat limited due to their cost and growth difficulties. For applications requiring waveguide geometries, further problems exist, as KNbO3 is not particularly suited to general fabrication techniques such as diffusion or ion exchange. Ion beam implantation has produced optical waveguides, and liquid phase epitaxy techniques prove successful, but so far, the technique of Pulsed Laser Deposition (PLD) has not been applied to thin film KNbO3 growth. We report here the results of waveguide growth using this technique.

Synthesis and characterization of tungsten disulphide films grown by pulsed-laser deposition

Abstract: The synthesis and characterization of tungsten disulphide (WS2) films grown on 440C stainless steel substrates using the 248 nm line from a KrF excimer laser are reported. Film properties could be adjusted by controlling substrate temperature and by laser or thermal anneals. X-ray photoelectron spectroscopy, glancing angle XRD, Raman spectroscopy and high-resolution scanning electron microscopy were used to evaluate film chemistry, crystallinity and morphology. Films grown at room temperature were amorphous, near stoichiometric, and had a multiplicity of chemical states. Local order and bonding were improved most dramatically through post-deposition laser anneals. Crystallite size could be increased by raising the substrate temperature during deposition and, to a lesser degree, by post-deposition thermal anneals. Local disorder was observed within the larger crystallites compared to those that were laser annealed. Crystallinity was induced in amorphous films by mechanical rubbing at room temperature under conditions where frictional heating was negligible. The degree of control over film properties provided by PLD demonstrates its value for growing/designing tribological coatings.

Plasma CVD of silicon nitride thin films on large area glass substrates at high deposition rates

Abstract: High quality silicon nitride thin films can be deposited by plasma CVD onto large area glass substrates at high deposition rates by adjusting the spacing between the gas inlet manifold and substrate, maintaining the temperature at about 300°-350° C., and a pressure of at least 0.8 Torr. Subsequently deposited different thin films can also be deposited in separate chemical vapor deposition chambers which are part of a single vacuum system.

Ion-assisted laser processing of CNx films

Abstract: We have produced CNx thin films with x = 0–0.70 by using an ion-assisted pulsed laser deposition method. In this method a graphite target was ablated while simultaneously bombarding the substrate with nitrogen ions. The deposition rate, ion current, substrate temperature and substrate bias were varied to enhance nitrogen incorporation and to optimize the properties of the thin films. The films were characterized using Rutherford backscattering-channelling. Auger electron spectroscopy, electron energy loss spectroscopy, transmission and scanning electron microscopy, Raman spectroscopy and nano-indentation hardness measurements. The average nitrogen concentration was found to vary (N/C atomic ratio) in the range 0–0.70. The transmission electron microscopy studies showed that these films were polycrystalline with a fine-grain equiaxed structure (average size 10 nm) above a substrate temperature of 200°C. The sp3/sp2 ratio was determined to be 25%–30% using electron energy loss spectroscopy. The Raman studies showed two peaks at 1285 and 1575 cm−1 corresponding to sp3 and sp2 bonding respectively. The films exhibited qualitatively very high hardness and thermal annealing resistance.

Disorder-Induced Low-Frequency Raman Band Observed in Deposited MoS2 Films

Abstract: Crystalline disorder in thin films plays an important role in determining their properties. Disorder in the crystal structure of MoS2 films prepared by magnetron sputtering and pulsed laser deposition was evaluated with the use of Raman spectroscopy. The peak positions and bandwidths of the first-order Raman bands, in the region 100 to 500 cm-1, were used as a measure of crystalline order. In addition, a low-frequency feature was observed at 223 cm-1 that is not part of the normal first-order spectrum of a fully crystalline specimen. Data presented here demonstrate that this band is characteristic of crystalline disorder, and its intensity depends on the annealing history of the film. This behavior seems to be analogous to the disorder found in graphite thin films.

Deposition of micrometer-sized tungsten patterns by laser transfer technique

Abstract: A simple single‐step technique for surface patterning is presented. It is shown that well‐adhering micrometer‐sized patterns of 100% coverage preserving the shape and dimensions of the ablated area can be deposited by ablating and transferring tungsten thin films in the form of single solid pieces using single pulses of peak power up to 100 mW and 100 μs–1 ms duration from a diode‐pumped YAG laser.

Polyperinaphthalene film formation by pulsed laser deposition with a target of perylenetetracarboxylic dianhydride

Abstract: Thin films of polyperinaphthalene (PPN) have been obtained by Nd:YAG pulsed laser deposition with a target of perylenetetracarboxylic dianhydride. Components of the films depend on the power and wavelength of the laser light, which is verified by absorption spectra, Raman scattering spectra, and in situ mass spectra. The optimum conditions for the PPN film formation is 10 mJ cm−2 at 266 nm.

Crystalline phases of II‐VI compound semiconductors grown by pulsed laser deposition

Abstract: II‐VI compound semiconductors, ZnS, ZnSe, CdS, CdSe, and CdTe, were grown epitaxially on (111) and (100) InP and GaAs substrates by excimer laser ablation. All of these films have good crystalline quality (fully in‐plane aligned) and mirror‐like surface morphology. It was found that, on (111)‐oriented substrates, CdS and CdSe films were in the hexagonal phase with the c axis perpendicular to the surface, while ZnS and ZnSe films were in the cubic phase. The films grown on (100)‐oriented substrates were all cubic. These high quality films should be useful in optoelectronics applications.

Crystallographic and Electrical Properties of Epitaxial BaTiO3 Film Grown on Conductive and Insulating Perovskite Oxides

Abstract: BaTiO3 films of various thicknesses were grown on doped and undoped SrTiO3(100) substrates and on (La, Sr)2CuO4 films by a pulse laser deposition method. Both BaTiO3 and (La, Sr)2CuO4 films were smooth and free of particulates. X-ray diffractometry showed that all materials were three-dimensionally aligned with the cube-on-cube epitaxial relationship, and that the films obtained on SrTiO3(100) were of a c-axis-oriented tetragonal phase contrary to previous studies using metal bottom electrodes. As the film thickness decreased, the tetragonality of these films increased and the dielectric constant along the c-axis decreased rapidly, despite reduction of disorder at the interface by use of perovskite electrodes. The 2000-A-thick BaTiO3 grown on (La, Sr)2CuO4 film had the remnant polarization of about 1.5 µ C/cm2. The results were discussed using a surface layer model.

Lateral structuring of silicon thin films by interference crystallization

Abstract: Laterally structured microcrystalline silicon in the submicron range has been produced from amorphous silicon thin films by transient holography using a high‐energy pulse laser. The energy density along the lines of the transient optical grid is sufficient to induce crystallization at the intensity maxima. Large area laterally structured microcrystalline silicon has been produced by selectively etching the amorphous phase with simultaneous growth of μc‐Si:H in a hydrogen‐silane plasma.

Pulsed laser deposition of high‐quality NbN thin films

Abstract: Pulsed laser deposition has been used to grow superconducting NbN thin films from niobium targets in a reactive gas atmosphere of N2 (10% H2). The structural and electrical properties of the deposited films have been determined as a function of substrate temperature and crystallographic orientation. Highly textured NbN was deposited on MgO (100). Films deposited on MgO at 600 °C in 60 mTorr gas pressure were characterized by Tc=16.6 K, Jc (4.2 K)=7.1 MA/cm2, and λ(0)=3200 A. Films grown on amorphous fused silica, under the same conditions, were polycrystalline and characterized by Tc=11.3 K and Jc (4.2 K)=1.8 MA/cm2.