Showing papers on "Sputter deposition published in 1978"

Magnetron sputtering: basic physics and application to cylindrical magnetrons

Abstract: Magnetron sputtering sources can be defined as diode devices in which magnetic fields are used in concert with the cathode surface to form electron traps which are so configured that the E×B electron‐drift currents close on themselves. Coaxial cylindrical magnetron sputtering sources in which post or hollow cathodes are operated in axial magnetic fields have been reported for a number of years. However, their performance is limited by end losses. A remarkable performance is achieved when the end losses are eliminated by proper shaping of the magnetic field or by using suitably placed electron‐reflecting surfaces. High currents and sputtering rates can be obtained, nearly independent of voltage, even at low pressures. This characterizes what has been defined as the magnetron mode of operation. This paper reviews the basic principles that underly the operation of dc sputtering sources in the magnetron mode with particular emphasis on cylindrical magnetrons. The important attributes of these devices as sputt...

Calculation of deposition rates in diode sputtering systems

Abstract: The scattering of sputtered atoms by the sputtering gas has been modelled to obtain values for the distances which the atoms travel normal to the sputtering target before their energies are reduced to the thermal energy of the gas. This distance increases with the mass and energy of the sputtered atom and with decreasing gas pressure; for a 5‐eV atom of mass 80, it decreases from 42 cm at an argon pressure of 0.1 Pa to 0.44 cm at 10 Pa. For most diode sputtering configurations, the sputtered atoms are thermalized before reaching the substrate and the transport to the substrate is by diffusion. Relative deposition rates for substrates situated behind apertures or masks in these diffusive sputtering situations have been measured and compared with the solid angles subtended at the substrate by the effective aperture. The agreement between relative values is very good. Thus, the solid angle provides a simple measure for determining the effect of a mask on the deposition profiles. Significant changes in rates and profiles are possible. With a 5‐cm‐square aperture, the rate at the center decreases by 50% as the substrate moves 2 cm away from the aperture plane and there is a 30% variation in rate over the substrate. It is impossible to obtain a sharply defined edge using a mechanical mask.

Planar magnetron sputtering

Abstract: The technology is reviewed with emphasis on implementation. PM sputtering is characterized by cathode potentials of 300–700 V and sputtering gas pressures of 1‐15 mTorr (0.1–2 Pa). Deposition rates are proportional to power density, which in turn is primarily limited by the thermal conductivity and cooling efficiency of the target. rf operating characteristics are similar to dc, but plasma plus target impedance is somewhat higher. For both rf and dc PM sputtering higher power (or current) densities are achievable at lower target potentials than for conventional sputtering. Permanent magnets and electro‐magnets have been used to produce closed electron‐trapping field patterns adjacent to the surface of both circular and rectangular planar targets. Plasma intensity and target erosion is a maximum where the magnetic field lines are parallel to the cathode surface. Deposition uniformity can be achieved by substrate motion combined with optimized magnet geometry. For a given material at equivalent deposition r...

Optical spectroscopy for diagnostics and process control during glow discharge etching and sputter deposition

Abstract: Applications and limitations of optical spectroscopy for process control, as well as for more fundamental investigations, of glow discharge sputter deposition and emission spectroscopies allows the determination of concentrations and spatial distributions of sputtered and background gas species in ground, metastable, ionized, and excited states Optical probing is a sensitive detection technique with good spatial resolution It has the advantage of providing in situ real time information without disturbing the discharge Examples of processes which may be monitored optically include: sputter etching and film deposition rates, net elemental sticking probabilities during bias sputter deposition, plasma ’’ashing’’ of photoresists, and reactive ion etching Optical spectroscopy has also been used as a diagnostic technique for investigating preferential sputtering of alloys, reactive gas–surface interactions, and for providing quantitative chemical analysis and depth profiling information

Feedback control for vacuum deposition apparatus

Abstract: Method and apparatus for controlling vacuum deposition of a thin film onto a substrate, wherein the vacuum deposition produces a glow discharge. The glow discharge is monitored and light therefrom is converted to an electrical signal which is compared to a preset reference signal and used to optimize thin film properties by controlling deposition parameters such as current between electrodes or the supply of gas to a reactive sputtering apparatus. The overall intensity of the glow discharge, or the intensity of certain wavelengths, or the ratio of certain wavelength intensities may be monitored. The time derivative of the electrical signal may be taken to quicken response to light changes. The method and apparatus of the present invention are particularly applicable to reactive sputtering. As an alternative embodiment in reactive sputtering, cathode voltage may be monitored instead of the light.

Influence of deposition conditions on sputter‐deposited amorphous silicon

Abstract: The electrical, optical, and photoelectronic properties of sputter‐deposited amorphous silicon films have been systematically related to deposition parameters for the case of pure Ar sputtering gas in an rf diode system. Variation of the sputtering gas pressure from 25 to 150 mTorr controllably and reproducibly increases the film resistivity 3 to 4 orders of magnitude and significantly decreases optical absorption for photon energies ≲1.6 eV. Similar film property improvements can be realized through the use of large substrate‐target spacings (∼10 cm) and substrate temperatures ≲500 °C. The film properties, however, are independent of deposition rate between 0.5 and 5 A sec−1. The influence of gas pressure and substrate‐target spacing has been linked to Ar bombardment of the growing film, which appears responsible for both high dangling‐bond densities and incorporated gas. The influence of substrate temperature could result from annealing of collision‐induced defects as the film grows, or from a decrease in the density of microvoids as reported by Paul et al. for amorphous germanium. The use of deposition conditions which minimize plasma interaction and maximize thermal reorganization results in remarkably good electrical and optical properties for nonhydrogenated amorphous silicon. Using the approach of Lewis et al. the addition of H2 to the Ar sputtering gas produces film properties which are further improved and quite similar to those observed for films prepared by plasma‐assisted decomposition of silane.

Apparatus for multilayer thin film deposition

Abstract: Apparatus for sputter depositing two or more layers of material onto a substrate in one operation includes an evacuable chamber containing a transport mechanism, substrate support, and at least two deposition units situated proximate the support. The transport mechanism moves the substrate to and from the support. When at the support, the substrate is passed by one deposition unit and then the other for sputter deposition of a thin film of material by each unit.

Method and apparatus for monitoring and controlling sputter deposition processes

Abstract: A system is provided for monitoring sputtering deposition parameters and through closed-loop control achieving rapid modification of the parameters to maintain or to obtain a film composition. In reactive sputtering, the sputtering chamber has individual gas pressure controllers for the various gases to be added to the chamber. A holder for a substrate on which the film is to be deposited includes a heater with adjustable control. A differentially pumped quadrupole mass analyzer interconnects with the chamber bottom to receive a sample of plasma ions, measures the ionized species existing in the plasma and generates signals related to the film composition. A controller responsive to the quadrupole analyzer actuation adjusts the pressure of the one or more reactive or non-reactive gases being provided to the chamber, and/or controls other deposition parameters, such as substrate temperature or other plasma features.

Cathode for sputtering

Abstract: A system for sputter coating architectural glass is disclosed which includes an evacuable enclosure, a conveyor for moving glass to be coated along parallel paths, an elongated sputtering cathode supported between the paths, and structure by which ionizable gas is introduced into the enclosure. The cathode creates a continuous band of plasma extending about it through a region defining laterally spaced first and second sections extending generally parallel to glass on respective sides of the cathode and return sections joining the ends of the laterally spaced sections. The cathode includes sputtering material target face portions extending adjacent and parallel to the plasma sections and a magnetic field directing system for constraining the plasma flow in the sections to extend substantially uniformly over the target face portions.

Magnetic properties of amorphous FeC thin films

Abstract: Thin films of amorphous FexC1−x (0.75⩽x⩽0.50) were prepared by sputter deposition. Room temperature values for 4πMs ranged from 13000 gauss (x=0.75) to 6500 gauss (x=0.50). Thus the room temperature magnetization is much higher than that for amorphous alloys of Fe with other group IV elements. The increased magnetization appears to be due to a higher Curie temperature as well as a larger atomic moment. It is well known that bulk amorphous samples of rapidly quenched alloys of transition metals with group III, IV and V elements can be prepared with low Hc; however, little is known of the properties of these alloys when prepared with thin films. We show that amorphous films of FeC can be prepared as Hc≈0.10 Oe without the need for post deposition annealing by proper selection of deposition parameters, in particular the argon gas pressure. The anisotropy energy is also dependent upon deposition gas presssure, going to zero for the same pressure that produces low Hc. Magnetostriction measurements have been ma...

Oxygen atom containing film for a thin-film electroluminescent element

Abstract: At least one silicon-oxynitride film is deposited on an electroluminescence layer for providing a uniform and stable dielectric layer for an electroluminescence display panel. The silicon-oxynitride film is deposited using a sputtering technique by mixing a small amount (1 mol%) of nitrous oxide (N2 O) gas into a sputtering gas such as nitrogen (N2) gas. Oxygen (O2) gas may be substituted for the N2 O gas mingled within the sputtering gas in the amount of five mol%. A target for sputtering is a pure silicon or sintered Si3 N4 plate. An R.F. discharge is provided so that the power flux density on the target becomes several to several ten W. The silicon-oxynitride film is derived by means of the reaction between ion sputtering and the sputtering gas. A dielectric layer is further provided for establishing high reliabiltiy high dielectric properties of the electroluminescence display panel, the dielectric layer being disposed together with the silicon-oxynitride film and being one of the group consisting of Al2 O3, SiO2, Ta2 O5, Si3 N4 and Y2 O3. The silicon-oxynitride flm which is injected by suitable ions such as P+, H+, He+, Ne+, or Ar+ may be further provided as the dielectric layer.

Closed-loop sputtering system and method of operating same

Abstract: A closed-loop sputtering system for the deposition of thin films which includes a control means to maintain and control the voltage of the target electrode by control of the flow of gas to the plasma without measurement of the pressure of the system.

Cathode target material compositions for magnetic sputtering

Abstract: A method for the magnetron sputtering of ferromagnetic material. An alloy of the ferromagnetic material is formed such that the alloy retains the desired characteristics of the material but the alloy has a Curie temperature that is below the sputtering temperature. In particular, the method can be applied to nickel by alloying the nickel with copper, platinum, or tin.

High resolution scanning electron microscopy in biology: artefacts caused by the nature and mode of application of the coating material.

Abstract: SUMMARY Results of high resolution secondary electron observations of the haemocyanin molecule from the marine whelk Buccinum undatum are given. The choice of metal used for surface coating of the sample (gold, gold-palladium or carbon/gold-palladium) and the mode of application of this metal (thermal vacuum evaporation or diode sputtering) were both found to be of utmost importance when working at high magnifications in the scanning electron microscope. Sputter coating with gold gives poor results because of a granular and cracked appearance of the surface film. The haemocyanin molecules were difficult to recognize in these preparations. Best results were obtained by a thermal vacuum evaporation of gold-palladium. It is suggested that the inferior results seen after sputter coating may be due to the high temperatures which the specimen experiences during the sputtering, even when cooling of the specimen stage is carried out. Other specimens (diatom valves and latex spheres) were also studied at high magnification giving the same results as the haemocyanin molecules.

Two-sided bias sputter deposition method and apparatus

Abstract: Method and apparatus for coating a thin film upon a substrate in a vacuum chamber using the sputter deposition technique on both sides of the substrate without rotation of the substrate. The substrate is held between two movable rams and is located between two targets equal to or larger in size than the substrate. The rams supply power and cooling to the substrate. A glow suppression ring circumscribes the periphery of the substrate. The cathodes of the sputtering system can be magnetically enhanced for concentration of the sputtering plasma.

Low‐field magnetic properties of sputter deposited amorphous Fe80B20

Abstract: Amorphous Fe80B20 alloy was obtained by sputtering deposition onto a copper substrate cooled by liquid nitrogen. At room temperature, the sample on the copper substrate was under tension because of the differential thermal expansion, so that the magnetic remanence was up to 90% of the saturation, and the dc coercivity was 22 mOe. These results, together with high crystallization temperature, make the sputter deposited Fe80B20 a very attractive soft magnetic material.

Surface relief gratings of 3200‐Å‐period fabrication techniques and influence on thin‐film growth

Abstract: As part of a project to study the effects of surface relief steps on thin‐film nucleation and growth, a technology for fabricating 1000‐A‐linewidth surface relief gratings with control of sidewall profiles to a resolution of the order of 100 A is under development. Laser holographic lithography and ion beam etching are used to produce gold gratings on 0.9‐μm‐thick polyimide membrane masks. Next, these masks are replicated using CuL or CK x‐ray lithography, thereby producing high aspect ratio relief gratings in PMMA having well‐defined vertical sidewalls. Surface relief structures are then produced on substrates by liftoff, ion beam etching, or reactive ion etching using the PMMA relief gratings. Such structures were decorated with gold nuclei using ion beam sputter deposition. The decoration experiments indicated a periodic variation in nuclei density and showed that the smoothness of the grating edges is of the order of 100 A.

Substrate heating in cylindrical magnetron sputtering sources

Abstract: The magnetic plasma confinement in magnetron sputtering sources makes the plasma ionization process very efficient and allows high sputtering rates to be achieved with reduced substrate heating, particularly in the cylindrical-post magnetron geometry where a virtual anode separates the substrates from the plasma. Heating flux measurements at typical substrate locations surrounding cylindrical-post magnetron sputtering sources were made for the argon sputtering of seventeen metals, representing a range of atomic masses, crystallographic structures and sputtering yields. The heating flux data are combined with deposition rate measurements and are reported as energy per coating atom deposited. They are consistently interpreted in terms of four basic heating processes: (1) heat of condensation; (2) sputtered atom kinetic energy; (3) plasma radiation; (4) ion neutralization and reflection at the cathode. Ion reflection becomes increasingly important for the high mass materials. The energy per atom deposited is independent of the deposition rate and the argon pressure and varies from 15 to 25 eV atom −1 for light metals to over 50 eV atom −1 for heavy metals with moderate sputtering yields. The sputtering efficiency is shown to be a useful concept in accounting for ion reflection. Comparative data are reported for sputtering with nitrogen and oxygen and for cylindrical-hollow magnetron sources. The energy per atom is relatively high in nitrogen and oxgyen sputtering because of a high sputtering efficiency and a reduced metal sputtering yield. The closer proximity of the plasma in hollow cathodes introduces a plasma bombardment contribution to the heating flux.