Showing papers on "Thin film published in 1981"

Long-Range Surface-Plasma Waves on Very Thin Metal Films

Abstract: The dispersion equation of injected surface-plasma waves that propagate on thin metal films has been solved as a function of the film thickness, and splitting of the modes into two branches is observed. For one branch the imaginary part of the propagation constant goes to zero as the thickness of the metal decreases. Reflectivity calculations agree with this result, which predicts that one can obtain propagation distances that are more than 1 order of magnitude larger than observed before.

Programmable cell for use in programmable electronic arrays

Abstract: An improved programmable cell for use in programmable electronic arrays such as PROM devices, logic arrays, gate arrays and die interconnect arrays. The cells have a highly non-conductive state settable and non-resettable into a highly conductive state. The cells have a resistance of 10,000 ohms or more in the non-conductive state which are settable into the conductive state by a threshold voltage of 10 volts or less, a current of 25 milliamps or less, for 100 microseconds or less. The cells in the conductive state have a resistance of 100 ohms or less. The cells have a maximum permittable processing temperature of 400° centigrade or more and a storage temperature of 175° centigrade or more. The cells are formed from doped silicon alloys including at least hydrogen and/or fluorine and contain from about 0.1 to 5 percent dopant. The cells can be plasma deposited from silane or silicon tetrafluoride and hydrogen with 20 to 150,000 ppm of dopant. Each cell in an array is a thin film deposited cell and includes an isolating device which can be a bipolar or MOS device or can be a thin film diode or transistor. The associated addressing circuitry also can be conventional bipolar or MOS devices or thin film deposited devices. The cells have a cell area of less than one square mil to provide a high cell packing density.

Apparatus for performing growth of compound thin films

Abstract: A method and an apparatus are provided for performing growth of compound thin films by alternately repeating separate surface reactions of the substances comprising the compound. A carrier gas affects a diffusion barrier between the surface reaction steps to be separated from each other. The gas phase diffusion barrier is also applied to separate the source regions of different reacting vapors both from each other and from the surface reaction zone.

Evidence for Exponential Band Tails in Amorphous Silicon Hydride

Abstract: The width of the conduction- and valence-band tails in amorphous silicon hydride are inferred from time-of-flight measurements of the temperature dependence of the electron and hole drift mobilities, and a multiple-trapping model of dispersive transport.

Submicroscopic pattern replication with visible light

Abstract: Contact imaging with visible light is possible at submicroscopic resolution because the near field of a radiating object contains information of sufficiently high resolution. In this paper we demonstrate this principle by contact imaging of planar submicroscopic metal patterns with blue light (400 nm). Experimental details are described for two experiments: (1) The shadow of an opaque pattern was recorded on a negative photoresist and developed using permanganate staining. (2) An image of a transparent metal pattern was imprinted onto a molecular dye layer, exploiting the fact that photochemical bleaching of the dye is inhibited by contact with the metal due to energy transfer. Development was by silver decoration. The resolution obtained was 100 nm with the photoresist, and 50 to 70 nm with the dye layer.

Acoustic bulk wave composite resonators

Abstract: This letter reports on a new and unique form of acoustic bulk wave resonator composed of a thin film of ZnO sputtered onto a thin Si membrane supporting structure. The piezoelectric ZnO is used to excite a longitudinal bulk wave which reflects from the free surface of the film and membrane. The structure thus forms an acoustical cavity which exhibits parallel and series electrical resonance responses at the ZnO film electrodes for both even and odd order modes. Fundamental resonant frequencies near 500 MHz have been achieved with parallel resonant Q’s over 9000. The temperature coefficient of resonant frequency was found to be −31 ppm for a Si to ZnO thickness ratio of six.

Structural investigation of thin films of diamondlike carbon

Abstract: Diamondlike carbon films produced both by ion‐beam technique and by radio‐frequency (rf) plasma decomposition of hydrocarbon gases (C4H10, C2H6, C3H8, and CH4) have been examined using the technique of transmission electron microscopy. Although these examinations indicate that these films are predominantly amorphous, both single‐crystal and polycrystalline diffraction patterns have been obtained from films of both types that indicate formation of several different phases. Some of these phases appear to be cubic and could be new forms of carbon. The results of secondary ion mass spectrometric analysis of carbon films produced by rf plasma decomposition of hydrocarbon gases are also discussed.

Plasma deposition apparatus

Abstract: A plasma deposition apparatus having a plasma formation chamber and a specimen chamber which are arranged separately. Gaseous material and microwave power are introduced to the plasma formation chamber to generate plasma by a microwave discharge through electron cyclotron resonance. The plasma is extracted to the specimen chamber from the plasma extracting orifice. In the specimen chamber, the plasma is accelerated by the effect of divergent magnetic field to irradiate the surface of the specimen so as to deposit a thin film on the specimen substrate. A high-quality thin film is formed with a high efficiency at a low temperature. Accordingly, a thin film can be deposited on a specimen substrate having a low heat resistivity. The plasma deposition apparatus is useful for manufacturing various kinds of electronic devices.

Methods and apparatus for forming thin-film heterojunction solar cells from i-iii-vi2 chalcopyrite compounds, and solar cells produced thereby

Abstract: Cellule solaire a film mince amelioree, a grande surface, procedes et appareil de fabrication de cette cellule, cette derniere possedant un rendement de conversion lumiere-energie electrique relativement eleve et caracterisee en ce que la cellule (30) comprend une heterojonction (34) du type pn formee i) d'une premiere couche semi-conductrice (35) comprenant un materiau presentant une activite photovoltaique choisie dans les materiaux de la classe des chalcopyrites I-III-VI2 ternaires qui est deposee sous la forme d'une couche mince a 'gradient de composition' dont l'epaisseur est de l'ordre d'environ 2,5 microns a 5,0 microns (= 2,5 (Alpha)ma 5,0 (Alpha)m) et dans laquelle la region inferieure (35a) du materiau photovoltaique comprend de preference une region de basse resistivite de materiau semi-conducteur du type p superposee par une region (35b) de resistivite relativement haute, un materiau semi-conducteur de transition du type n definissant une homojonction de transition pn; Thin film solar cell has improved has large area, processes and manufacturing apparatus of this cell, the latter possessing an electric light-energy conversion efficiency relatively high and is characterized in that the cell (30) comprises a heterojunction (34) Type pn FORMED i) a first semiconductor layer (35) comprising a material having demonstrated a photovoltaic activity in the materials selected from the class of chalcopyrite I-III-VI2 ternary which is deposited as a thin layer 'composition gradient' whose thickness is of the order of about 2.5 microns to 5.0 microns (= 2.5 (Alpha) my 5.0 (Alpha) m) and wherein the lower region ( 35a) of the photovoltaic material preferably comprises a region of low resistivity semiconductor material of p-type superimposed by a region (35b) of relatively high resistivity, transition semiconductor material of n-type defining a transition pn homojunction; et ii) d'une seconde couche semi-conductrice (36) comprenant un materiau semi-conducteur a basse resistivite du type n; and ii) a second semiconductor layer (36) comprising a semiconductor material has low resistivity n-type; l'interdiffusion a) entre les constituants elementaires entre les deux regions discretes juxtaposees de la premiere couche semi-conductrice (35) definissant une couche de transition d'homojonction pn et b) entre le materiau de transition de type n dans la premiere couche semi-conductrice (35) et la deuxieme couche semi-conductrice (36) du type n, provoque la conversion du materiau de transition du type n dans la premiere couche semi-conductrice (35) en materiau de type p, definissant ainsi un dispositif a film mince a heterojonction caracterise par l'absence de vides, de lacunes et de nodules qui tendent a reduire le rendement de conversion du systeme. interdiffusion a) between the elementary constituents between the two juxtaposed discrete regions of the first semiconductor layer (35) defining a transition layer of pn homojunction and b) between the n-type transition material in the first semiconductor layer -conductrice (35) and the second semiconductor layer (36) of n-type material causes the conversion of n-type transition in the first semiconductor layer (35) in p-type material, and defining a device thin film characterizes HETEROJUNCTION by the absence of voids, gaps and nodules which tend to reduce the system conversion efficiency.

Tunneling hot electron transfer amplifiers (theta): Amplifiers operating up to the infrared

Abstract: A family of novel three-terminal devices which relies on the transfer of a quasi-monoenergetic hot electron beam through a thin base is described. The devices are similar in principle to the proposed tunneling amplifier by Mead in the early sixties (“Cold Cathode” or “Metal Base” amplifiers). Results are reviewed and the probable reasons for the poor performances are pointed out. It is predicted that, with a proper choice of parameters, metal-base amplifiers can operate as switches, negative resistance devices and continuous amplifiers in the subpicosecond range. Two subclasses are described: The tunneling emitter (THETA), in the major part of the work, and the nontunneling emitter (BHETA) amplifiers. In the THETA family the metal-oxide-metal-oxide-metal (MOMOM), the MOM-semiconductor (MOMS), and the heterojunctions devices are described. Members of the BHETA family generate quasi-monoenergetic electron beams by injecting electrons by an n + n − or a metal- n − junctions, and include a variety of metals and semiconductor combinations. Very thin films are required in these devices (oxides ∼15 A, metals ∼100 A, semiconductors ∼100 A). The molecular beam epitaxy technique and lattice matching considerations are required for pinhole free semiconductors and metal films with minimum interface states. Sputter-oxidation methods are needed for thin oxide growth. Systems which combine these features with availability of microfabrication make these devices feasible today.

Plasma Si nitride—A promising dielectric to achieve high-quality silicon MIS/IL solar cells

Abstract: Substantial advantages of plasma Si nitride, for the first time applied to silicon MIS inversion layer (MIS/IL) solar cells, are demonstrated: The highest positive interface charge densities ever used for this type of solar cell (up to 72×1012 cm−2), absolute stability of the charges up to the nitride despoition temperature (220 and 300 °C, respectively), excellent passivation of the entire cell, and good AR coating properties High uv sensitive MIS/IL solar cells were fabricated with these layers on p–Si (100) AM1 efficiencies of 15% (active area) at 25 °C were obtained

Phase separation of polymer blends in thin films

Abstract: Films of polystyrene-poly(vinylmethyl ether) blends of various compositions are formed by a dip-coating procedure, the thickness of the film being controlled by the concentration of the solution. The substrates used are glass and gold. The phase separation process is followed by a laser light scattering experiment in which the total forward scattering intensity is monitored as a function of temperature. Morphological examination shows that phase separation occurs by a spinodal decomposition mechanism. A thickness effect on the phase separation temperature is noticeable when film thickness is smaller than 1 μm. This effect is substrate dependent. In all films formed on gold the spinodal temperature increases as film thickness decreases. Films formed on glass exhibit a destabilizing effect on decreasing film thickness. This effect is slight in films of composition poorer in polystyrene than the critical composition, and is enhanced in films richer in polystyrene. The stabilizing effect of decreasing the thickness of films formed on the gold substrate is considered to reflect mainly a purely geometrical effect. The decreasing dimensionality is shown by simple theoretical considerations to increase the phase-separation temperature. However, the phase separation behavior of thin films on glass appears to be the result of two kinds of substrate-polymer interactions in addition to the geometrical effect: (a) electrostatic interaction of the charged glass surface (a destabilizing effect at all film compositions) and (b) selective adsorption of polystyrene on glass.

Ion beam deposition of special film structures

Abstract: The structure and properties of thin solid films deposited in vacuum can be influenced substantially if additional energy and momentum is provided to the growing layers by energetic, inert or film‐forming species. Various ion beam configurations for investigating these effects are discussed. Recent results are presented in conjunction with the following special film structures: (1) epitaxial, graphoepitaxial, and hydrogenated amorphous silicon deposits; (2) hard and unusual films of carbon and of boron nitride. Though the basic structure of the latter films is quasi‐amorphous, microcrystals of high‐pressure phases could be detected. Further trends are outlined.

Infrared optical properties of evaporated alumina films

Abstract: The dielectric function ∊ = ∊1 + i∊2 has been determined for Al2O3 films prepared by electron beam evaporation, in the 5–50-μm wavelength range. The data were extracted from spectrophotometric recordings of transmittance and reflectance by use of a novel technique. Supplementary measurements were made of the refractive index for visible and near-infrared wavelengths and of the dielectric constant at 1 MHz. Kramers-Kronig analysis was employed to check the consistency of our results for ∊1 and ∊2.

Method for manufacture of ultra-thin film capacitor

Abstract: A suitable substrate is provided to which is applied a metal electrically conductive film electrode. The substrate and electrically conductive electrode film are then exposed to ion beam implantation of O+ or N+ ions to impregnate the surface of the metal electrode with O+ or N+ ions. Thereafter, the substrate and electrically conductive film having implanted O+ or N+ ions is annealed so as to stabilize the oxide structure which has been implanted into the surface of the electrically conductive film to provide an ultra-thin dielectric film.

Pulsed laser-induced damage to thin-film optical coatings - Part I: Experimental

Abstract: We report a parameteric investigation of the damage threshold and morphology of nine frequently employed dielectric coatings as a function of pulse length (5 and 15 ns), frequency (1.06, 0.53, 0.35, and 0.26 μm), and film thickness. A vidicon camera and computer were used to obtain real-time laser spatial profiles for each testing event. This technique greatly reduced the time required to obtain damage thresholds and enabled a large matrix of data to be obtained. The data and damage morphologies are discussed and several important conclusions are drawn concerning pulsed laser-induced damage to optical materials in thin-film form.

Depth profile composition studies of thin film CdS:Cu2S solar cells using XPS and AES

Abstract: Surface composition and depth profile studies of hemiplated thin film CdS:CuzS solar cells have been carried out using x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) techniques. These studies indicate that the junction is fairly diffused in the as-prepared cell. However, heat treatment of the cell at 210°C in air relatively sharpens the junction and improves the cell performance. Using the Cu(2p3p)/S(2p) ratio as well as the Cu(LVV)/(LMM) Auger intensity ratio, it can be inferred that the nominal valency of copper in the layers above the junction is Cut and it is essentially in the CUSS form. Copper signals are observed from layers deep down in the cell. These seem to appear mostly from the grain boundary region. From the observed concentration of Cd, Cu and S in these deeper layers and the Cu(LVV)/(LMM) ratio it appears that the signals from copper essentially originate partly from copper in CuS and partly from Cu2t trapped in the lattice. It is significant to note that the nominal valence state of copper changes rather abruptly from Cut to Cuz+ across the junction.