Showing papers on "Pulsed laser deposition published in 1984"

Growth of epitaxial films by chemical vapor deposition utilizing a surface cleaning step immediately before deposition

Abstract: A method and apparatus for low temperature deposition of epitaxial films using low pressure chemical vapor deposition (CVD) with and without plasma enhancement. More specifically, the process enables CVD of epitaxial silicon at temperatures below 800° C. by use of an in situ argon plasma sputter cleaning treatment of the silicon substrate prior to deposition.

Co-Cr perpendicular magnetic recording tape by vacuum deposition

Abstract: The relation between the incident angle and the crystallographic orientation of a vacuum deposited Co-Cr film is discussed. Also presented are the magnetic properties and the orientation of both a Ni-Fe underlayer and the Co-Cr film for the double layer medium, and the experimental results about the composition distribution in the co-cr film. The films were deposited on a transporting polymer substrate by continuous vacuum deposition. It is found that the orientation of the Co-Cr film is determined only by the incident angle at the initial point of the film formation, and that deposition efficiency more than 50% can be achieved easily. A double layer medium with Ti film under the Ni-Fe film (Co-Cr/Ni-Fe/Ti medium), which is suitable for perpendicular magnetic recording, is produced by vacuum deposition. Auger depth profile in radial direction of the column of the Co-Cr film shows directly that there is Cr segregation near the columnar grain boundaries.

Apparatus for plasma assisted evaporation of thin films and corresponding method of deposition

Abstract: An improved method of and apparatus for depositing thin films, such as indium tin oxide, onto substrates, which deposition comprises one step in the fabrication of electronic, semiconductor and photovoltaic devices. The method includes the novel steps of combining the use of (1) an electron beam to vaporize a source of solid material, and (2) electromagnetic energy to provide an ionizable plasma from reactant gases. By passing the vaporized solid material through the plasma, it is activated prior to the deposition thereof onto the substrate. In this manner, the solid material and the reactant gases are excited to facilitate their interaction prior to the deposition of the newly formed compound onto the substrate.

Comparison of laser-initiated and thermal chemical vapor deposition of tungsten films

Abstract: ArF excimer laser radiation has been used to deposit W films on silicon and on SiO2 by initiating the gas phase reaction of WF6 with H2 Deposition rates >100 nm/min and film resistivities as low as two times the bulk value have been obtained at deposition temperatures of 440 °C The properties of the laser‐deposited films are compared with those of fims obtained using conventional thermal deposition techniques Film resistivity correlates with the microstructure which in turn depends on the deposition temperature; above 350 °C the low‐resistivity α‐W phase dominates

Thin film deposition

Abstract: In a thin film deposition apparatus, means for depositing a film on a substrate and means for etching the deposited film to make flat the surface thereof, are provided in a reaction vessel independently of each other. This apparatus can rapidly deposit the film without rising the temperature of the substrate excessively. Further, since the deposition means and etching means are independent of each other, the deposition of a film on the substrate and the planarization of the surface of the deposited film can be achieved under various conditions.

Low temperature plasma chemical vapor deposition of silicon oxynitride thin-film waveguides

Abstract: The use of plasma chemical vapor deposition (PCVD) of silicon oxynitride (SixOyNz) thin films on Si substrates at the very low temperature of 200°C is reported. Such a low deposition temperature would allow these films to be deposited on substrates with low decomposition or melting temperature. This is particularly significant to some of the important III–V compounds such as GaAs and InP. Another advantage of this low temperature deposition process is that undesired diffusion of dopants already present in the semiconductor substrates is reduced during film deposition. The details on the deposition procedures and the optical characteristics of the films are reported in this paper.

Low‐temperature silicon epitaxy using low pressure chemical vapor deposition with and without plasma enhancement

Abstract: Specular epitaxial silicon films have been deposited at 775 °C using a low pressure chemical vapor deposition process both with and without plasma enhancement. This is the lowest silicon epitaxial deposition temperature reported for thermally driven chemical vapor deposition. It was found that the predeposition in situ cleaning of the surface, rather than any plasma effects during the deposition, was essential for achieving epitaxial growth at this low temperature. Surface cleaning in these experiments was done by sputtering the wafer in an argon plasma at 775 °C with a dc bias applied to the susceptor. This is the lowest pre‐epitaxial cleaning temperature reported for thermally driven chemical vapor deposition.

Shield for improved magnetron sputter deposition into surface recesses

Abstract: A system for vacuum depositing a material onto a sample having a surface recess, such as a hole or channel, therein. The system includes a vacuum chamber capable of attaining a high vacuum and a vacuum deposition source in the chamber for emitting atoms. An energy source is connected to the vacuum deposition source to initiate emission of the atoms therefrom. A sample having an upper surface disposed in the vacuum chamber opposite the vacuum deposition source is adapted to receive the atoms emitted from the vacuum deposition source. The sample has a surface recess therein with a wall substantially perpendicular to the plane of the sample. Finally, a component for eliminating undesirable depositing angles of atoms is disposed intermediate the vacuum deposition source and the sample in order to improve the ratio of recess wall to sample surface deposition. Another important feature of the component for eliminating undesirable depositing angles is its ability to reduce heat generated on the sample during the deposition process.

Photo-Induced Chemical Vapor Deposition of SiO 2 Film Using Direct Excitation Process by Deuterium Lamp

Abstract: An attempt has been made on a low-temperature photo-induced chemical vapor deposition of SiO2 thin films by direct excitation without Hg sensitization under irradiation of a deuterium lamp having high energy photons. The film growth has been confirmed at 84°C and the substrate temperature for a considerably good film quality was above 170°C. The deposition rates and the refractive indices of the films deposited above about 170°C are about 100 A/min. and 1.44–1.46, respectively. Infrared absorption peaks related with Si–H bonding don't appear in the photo-CVD film deposited above 175°C, but appear in the thermal CVD film deposited at 175°C.

Process for forming an organic thin film

Abstract: An organic thin film consisting essentially of an organic compound is formed on a substrate surface by vacuum vapor deposition by exposing the organic compound as a vapor source to a laser beam having an energy level corresponding to that of the chemical bond of the organic compound, thereby sputtering the organic compound onto a substrate surface in vacuum and forming the organic thin film thereon. When a light or radiation-sensitive organic compound is used as the vapor source, a light or radiation-sensitive resist film is formed. The thin film thus formed retains the original chemical structure of the vapor source, and has a good flatness. Resolvability of resist film is improved owing to the absence of pin holes and particulate matters. A resist film having a higher sensitivity and a better contrast is formed by heating the substrate during the vapor deposition.

Optical and thermal effects in laser chemical vapor deposition

Abstract: In laser chemical vapor deposition (LCVD), a laser is used to drive a deposition reaction by locally heating the substrate. Although the reactant systems used may be similar to conventional CVD, the film growth characteristics may differ in several ways. The changes in the optical properties of the film/substrate during deposition must be considered as the amount of laser energy absorbed determines the surface temperature and therefore the deposition rate. Also affecting the deposition rate is the diffusion of reactants to the reaction zone. Because of the small area heated in LCVD, higher surface temperatures can be accessed before diffusion and convection limit the deposition rate. For favorable reactant systems, very rapid deposition rates (greater than 100 ..mu..m/sec) and scan speeds for line deposition (greater than 10 cm/sec) can be achieved. 24 references, 5 figures, 2 tables.

Structure of Platinum and Tin Films Formed by Laser-Induced Chemical Vapor Deposition

Abstract: Working integrated circuits have recently been produced by LCVD techniques (1), and much of the laser chemistry effort at the gas-solid and liquid-solid interfaces is directed towards this goal (2–4). In the present communication we report on the LCVD of Pt and Sn by observing the deposited thin films using electron microscopy. The dependence of the structure of the metallic deposit on the following variables is measured: A) The LCVD mechanism which can be either pyrolytic or photolytic. B) The laser irradiation time. C) The laser power density at the surface. The dependence of the LCVD on the gas pressure in these experiments has been reported elsewhere (5). In a future paper we will try to correlate the observed structures of the metallic deposits with their electric conductivity (6).

Laser Chemical Vapor Deposition Using Continuous Wave And Pulsed Lasers

Abstract: The deposition rate in laser chemical vapor deposition (LCVD) is a function of the surface temperature and therefore also a function of the chang-ing reflectivity of the surface during deposition. The influence of these parame-ters on the LCVD rate of metallic and insulating thin films was investigated using both pulsed and cw laser sources and optical monitoring of the depositing film thickness. Physical properties of the LCVD films are reported.

Raman Studies of Internal Stress and Crystallinity of Pulse-Laser-Irradiated Silicon on Sapphire (SOS) in Relation to Hall Mobility

Abstract: The changes in internal stress and crystallinity in silicon- on-sapphire (SOS), as caused by pulse laser irradiation, were evaluated by Raman spectroscopy. The vertical distributions of the internal stress and the crystallinity in the silicon layer were found to be significantly affected by the number of laser pulses, although the energy density and width of the laser pulses were kept constant. The change in electron Hall mobility due to laser irradiation is discussed in relation to the internal stress and crystallinity of the SOS. An excessive number of pulses causes a reduction in the orientational order of the constituent crystallites in the silicon layer, with a decrease in the electron Hall mobility.

Pulse Laser Annealing Effects in Si-Implanted GaAs

Abstract: The effects of pulsed ruby and Nd:Glass laser irradiation on the electrical properties of Si-mplanted GaAs were investigated to reveal the reason for the lack of activity in low-dose-implanted samples after pulsed-laser annealing. High electrical activity was observed in a sample implanted at a dose of 1015/cm2, while no activity was observed in a sample implanted at a dose of less than 1014/cm2 after the same pulsed laser annealing process. It was found that the ruby laser irradiation of a thermally-annealed sample greatly reduces the carrier concentration and mobility near the surface, while Nd: Glass laser irradiation does not. It is suggested that the surface melting and recrystallization that takes place at a high rate of cooling in pulsed annealing induces defects, giving rise to the lack of activity and low mobility in laser-annealed GaAs.

Marking to semiconductor substrate by laser light

Abstract: PURPOSE:To form the marks in the specified depth with a low energy laser light by irradiating the same area of semiconductor substrate with plural pulse laser lights where the laser light spot diameters in each pulse are sequentially set smaller. CONSTITUTION:The area where the mark (c) on the semiconductor substrate (a) is irradated with the one pulse of first laser light L1. The first recessed area 12 is irradiated with one pulse of second laser light L2 in the same optical axis with the first laser light L1. The bottom part of the second recessed part 13 is irradiated with third laser light L3 of which energy is the same or lower than the second laser light L2 and spot diameter D3 is smaller than that of the spot diameter D2 of second laser light L2. Thereby, the third fused material 16 is deposited in the periphery of said third recessed area 15. Moreover, the bottom part of third recessed area 15 is irradiated with the fourth laser light L4 of which energy is the same or lower than the third laser light L3 and sopt diameter D4 is smaller than that of the third laser light L3. Thereby, the fourth fused material 18 is deposited in the periphery of the fourth recessed part 17.

Method and device for forming protectional film

Abstract: PURPOSE:To form a protection film continuously, stably with good repro ducibility without damaging a base by evaporating a target composed of an organic high polymer in vacuum with irradiation of laser beams and depositing it on the surface of the base to be protected. CONSTITUTION:A target 5 composed of an organic high polymer of an evaporation depositing source, installed in a vacuum drum 4 with an evacuation system 6 is irradiated by a laser beam, which is generated from a laser beam source 1 through a synthetic quartz lens 2 and a synthetic quartz window 3 and evaporated and spattered in the vacuum. Accordingly, a magnetic recording tape 7 is transferred continuously by rolls 8, 9 as a base, and an evaporated material of the organic high polymer spattered on the surface is deposited to form a protection film. To form the protection film, a CO2 laser beam of 1-10 Pa at the degree of vacuum in the vacuum drum 4, of >=0.5J/cm and 150-400nm in the wavelength of the laser beam is suitable.

Laser beam machine

Abstract: PURPOSE:To obtain a titled machine for reducing an output loss of a laser, perform plural laser machining and improve the productivity by providing a rotary chopping reflecting mirror for making a part of a laser beam transmit and a total reflecting mirror of a transmitting beam on a laser beam path, and converting it to a pulse laser beam. CONSTITUTION:A continuous laser beam 8 of a laser beam path is reflected and divided into pulse laser beams 8A, 8B by a rotary 3 chopping mirror 4 for making a part of said beam transmit 4a and reflecting totally a part of same, and a total reflecting mirror 5, and plural objects 7 to be worked are brought to pulse laser machining, respectively. A laser oscillator can execute a continuous oscillation, reduces an output loss of a laser, can perform plural laser beam machining, and improves the productivity. In this regard, it is also possible to change a shape of a transmitting beam hole of the chopping mirror and to increase its number to three pieces or more.

Fluorine-doped fibers by the outside vapor deposition process

Abstract: Fluorine-doped depressed-index claddings have been widely used in the inside vapor deposition process. This paper reports on fluorine-doped fibers made by the outside vapor deposition (OVD) process. The advanced segmented-core (Segcor) fiber design reported earlier,1 which produces large spot sizes and propagation constants along with low total dispersion between 1.3 and 1.6 μm, requires off-axis index depressions. Until recently, the formidable problems associated with fluorine doping in flame hydrolysis reactions have excluded such complex designs. Through process modifications, fluorine-doped silica core and claddings have now been incorporated into OVD produced fibers.

Metal Deposition By Laser Driven Pyrolysis Of Solid Organometallic Films

Abstract: The localized deposition of metal and metal oxide films by laser thermal decomposition of a solid organometallic film has been investigated. Several different laser sources have been used to irradiate commercially available organometallic resinate films applied using standard photoresist techniques on glass and quartz substrates. The focused laser causes localized decomposition of the organometallic film and the unreacted film is removed with solvent. Decomposition occurs stepwise with the initial state being insoluble but opaque and nonconducting. Continued irradiation results in metallic appearing films. Film dimensions considerably less than the laser spot diameter could be be produced under appropriate irradiation conditions.

Manufacture of si semiconductor

Abstract: PURPOSE: To obtain an Si semiconductor which has greater electron mobility and the mobility is not reduced even exposed at a high temperature by irradiating pulse light on an Si layer under the conditions that an insulation substrate is cooled or that the insulation substrate is dipped with the Si layer in a refrigerant. CONSTITUTION: An insulation substrate 15 formed with an Si layer 16 is dipped in liquid nitrogen 13 and pulse laser light 10 is irradiated toward the Si layer 16 three times. Since the liquid nitrogen is permeable against ruby laser light, the light arrives at the surface of Si with almost no loss and the Si layer is repeated melting and recrystallization by every irradiation. Consequently, the mobility of a hole in the atmosphere of a room temperature is approx. 1.5 times improved in comparison with the mobility when irradiated by pulse laser light of the same energy density. For example, the mobility even heated at 700°C is not reduced under the value before heating in the case of room temperature irradiation. COPYRIGHT: (C)1985,JPO&Japio

Redundancy circuit device

Abstract: PURPOSE:To enable a writing to a conductive state from a non-conductive state at a high rate of success by forming a p-n junction under a reverse bias state diffused and formed from the surface of a semiconductor substrate and a protective film of specific film thickness formed to the surface of the substrate on the junction section. CONSTITUTION:An n type impurity is diffused to the substrate 11 from the opening section of a field silicon oxide film 12, and an n type diffusion region 15 of approximately 0.5mum diffusion depth is formed. The substrate 11 and the diffusion region 15 are each wired properly so that the p-n junction section formed by the diffusion region 15 and the semiconductor substrate 11 is brought to a reverse bias state. The protective film 14 of a silicon oxide film is formed to the whole surface on the substrate 11 in film thickness of 0.5mum or more. When YAG pulse laser beams are irradiated selectively to said p-n junction section, they do not scatter when the thickness of the protective film 14 is made 0.5mum or more, a crystal is damaged, and stable junction leakage currents Il are obtained positively. when the diffusion depth of said n type diffusion region 15 reaches 1.0mum or more, the p-n junction is made difficult to be damaged through laser irradiation.

Material vapor deposition technique.

Abstract: Deposited layers are advantageously obtained by utilizing a specific vapor deposition procedure. In this procedure, a substrate is positioned a relatively short distance from the source of a gas flow capable of producing the desired deposition. This gas flow is directed so that it contacts an interior region of the substrate and moves from the initial contact point to a point on the periphery of the substrate. Exemplary of such gas flow configurations is the positioning of a substrate (23) at a small distance above a fused quartz frit (101) through which the deposition gas flow (30) is directed.

Some properties of a-Si: C films prepared by vacuum deposition with simultaneous substrate bombardment by electrons'

Abstract: Films of a-Si:C have been prepared by vacuum deposition while the substrate was simultaneously bombarded with 1000-V electrons. Some film properties (electrical, optical) are compared for films deposited both with and without electron beam irradiation. It is concluded that the effect of the electron beam irradiation is to produce a film with a structure closer to that of an ideal random network. Some of the films are photoconducting and have undoped electrical characteristics similar to those of a-Si:H.

Epitaxy and Defects in Laser-Irradiated, Single-Crystal Bismuth

Abstract: The (0001), ( $$\overline 1 010$$ ), and ( $$2\overline {11} 0$$ ) faces of Bi have been pulse laser melted at 0.5 J/cm2 with a Q-switched Ruby laser. Nomarski Interference Contrast Microscopy, Channeling, and selective chemical etching have been used to investigate the response to the laser irradiation. The response of the material and the level of damage is shown to be strongly correlated to the critical resolved shear stress characteristics in the particular crystallographic direction studied.