Showing papers on "Sputter deposition published in 1983"

Properties of tin doped indium oxide thin films prepared by magnetron sputtering

Abstract: Indium tin oxide (ITO) films have been prepared by the magnetron sputtering technique from a target of a mixture of In2O3 and SnO2 in the proportion 9:1 by weight. By optimizing the deposition conditions it has been possible to produce highly transparent (transmission ∼90%) and conducting (resistivity ∼10−5 Ω cm) ITO films. A resistivity ∼10−4 Ω cm has been obtained for films of thickness ∼1000 A at a comparatively low substrate temperature of 50 °C and without using oxygen in the sputtering chamber. To characterize the films, the following properties have been studied, viz., electrical conductivity, thermoelectric power, Hall effect, optical transmission, and band gap. The effect of annealing in air and vacuum on the properties of the films have also been studied.

Method for forming photovoltaic cells employing multinary semiconductor films

Abstract: At least two constituent elements of a semiconductor compound are deposited in varying proportions by magnetron sputtering to produce a film having a preselected concentration gradient of the constituent elements. The film can be heat treated during or after deposition to diffuse the constituent elements within the film and enhance growth of a desired film structure. The sputtering step may be performed using a planar magnetron having a plurality of continuous magnetically enhanced sputtering cathodes extending about a common axis. Each of the cathodes includes a source structure containing at least one of the constituent elements, and provision for applying electrical power to the source structure to sputter the constituent element at a controlled rate. If one of the elements is difficult to control in the deposition process, it can be sputtered from a cathode made up of a stable alloy of the element and another constituent of the film. For example, when the semiconductor compound is CuInSe2, two of the sputtering cathodes may comprise In2 Se3 and Cu2 Se, respectively, and a third optimal cathode comprises either Cu or In.

Quantitative ion beam process for the deposition of compound thin films

Abstract: We describe a quantitative ion beam technique for the deposition of compound thin films. The metal atom flux is supplied by inert ion beam sputtering, and the reactive flux is supplied by a low‐energy ion beam directed at the growing film, allowing the fundamental deposition parameters of arrival rates, ion energy, and direction to be measured and controlled. Analysis gives the sputtering yields and incorporation probabilities as a function of film composition, arrival rate ratios, and ion energy. Results are presented for Al films deposited under a range of N2+ ion bombardment (100–500 eV) up to arrival rate ratios exceeding the value needed to form AlN. Nitrogen ions are almost fully incorporated into Al films, and excess N is rejected above the composition N/Al=1. The microstructure is shown to depend on the N/Al arrival rate ratio and the nitrogen ion energy used during deposition.

Plasma deposition method and apparatus

Abstract: A plasma deposition apparatus comprising a plasma formation chamber into which a gas is introduced to produce plasma, a specimen chamber in which a specimen table is disposed for placing thereon a speciment substrate on which a thin film is to be formed, a plasma extraction window interposed between the plasma formation chamber and the specimen chamber, a target which is made of a sputtering material and is interposed between the plasma extraction window and the specimen table, a first means for extracting ions for sputtering the target from a plasma stream extracted from the plasma formation chamber to impinge against the target, and a second means for extracting the plasma stream through the plasma extraction window into the specimen chamber and for transporting the sputtered and ionized atoms to the specimen substrate period on the specimen table. A high quality thin film of various metals and metal compounds can be formed at a low temperature and a thin film is formed, while characteristics or properties of the thin film to be formed is controlled.

Properties of NbN thin films deposited on ambient temperature substrates

Abstract: The preparation of cubic NbN films by reactive dc magnetron sputtering is described. These superconductive films are deposited at a sufficiently low temperature (<90 °C) that photoresist liftoff techniques and can be used in fabricating Josephson junctions. The superconducting transition temperature has been measured as a function of gas composition and pressure. It reaches a maximum of 14.2 K at 15% N2–85% Ar and 1.06 Pa total pressure. The resistivity ratio of these films is close to unity. Structural studies by transmission electron microscopy and electron diffraction show that films 100‐nm thick or less are randomly oriented, and noncolumnar with a crystallite diameter of 5 nm and a lattice parameter of 4.46 A, which is significantly higher than the bulk value for cubic NbN. The films are dense with void diameters no larger than 0.7 nm. Films 300‐400 nm thick show a small degree of texturing in x‐ray studies with a Read camera. Auger analysis shows a monotonic increase in the N/Nb ratio with increase in the N2/Ar ratio in the sputtering ambient up to 30% N2. From 30% to 50% N2 in the sputtering mixture the N/Nb ratio is constant. Small amounts of carbon impurity are found in all films.

Photo-assisted CVD

Abstract: A process and apparatus for depositing a film from a gas involves introducing the gas to a deposition environment containing a substrate, heating the substrate, and irradiating the gas with radiation having a preselected energy spectrum, such that a film is deposited onto the substrate. In a preferred embodiment, the energy spectrum of the radiation is below or approximately equal to that required to photochemically decompose the gas. In another embodiment, the gas is irradiated through a transparent member exposed at a first surface thereof to the deposition environment, and a flow of substantially inert gaseous material is passed along the first surface to minimize deposition thereon.

Determination Of Atomic Lifetimes Using Laser-Induced Fluorescence From Sputtered Metal Vapor

Abstract: A detailed description is given of a recently established life-times method, in which the time decay of atomic fluorescence is recorded following pulsed laser excitation of an atomic vapor produced by cathodic sputtering in a rare-gas discharge. The method is readily applicable to neutral and singly ionized atoms of a wide range of elements, including the highly refractory elements for which, until very recently, little lifetime data have been available. A theoretical discussion is presented of the form of the time-resolved fluorescence signal detected following pulsed laser excitation of a group of atoms, with particular emphasis on possible sources of distortion in the fluorescence decay curves. Ex-amples are given of lifetime measurements on both neutral and singly ionized atoms of a number of refractory elements and comparisons made with other recent laser-induced fluorescence measurements. Some new lifetime data are reported for levels in Zr I, Zr II, Ag I, and Cu I.

Epitaxial crystal growth by sputter deposition: Applications to semiconductors. Part 2

Abstract: The process of sputtering may be defined as the ejection of target particles due to the impingement of energetic projectile particles. The use of sputtered species as source material to deposit thin films was first reported in the literature in 18521 and has since enjoyed several periods of scientific and commercial interest interspersed with periods of disrepute. However, it is only recently that sufficient understanding of the complex processes occurring during, and simultaneously with. ion bombardment of solid surfaces has developed to result in the ability to reproducably and controllably use sputter deposition to grow high quality single crystal semiconducting thin films. The evolution of the branch of science concerned with ion‐surface interactions has been facilitated by the parallel development of ultra high vacuum technology and highly sensitive microanalytic techniques for identifying the state of scattered particles, sputtered species, and implanted material.

Structure and coherence of NbAl multilayer films

Abstract: NbnAlm multilayer films grown on oxidized Si(100) at room temperature by magnetron sputtering have Nb[110] and A[111] texture. The films have ∼1% coherency strains which decrease with increasing modulation wavelength. The composition modulation is approximately a trapezoidal wave with interfacial regions ∼11 A thick as a result of grain boundary diffusion.

Rf sputtering–voltage division between two electrodes

Abstract: In a dc sputtering system only the cathode is bombarded by positive ions. However, in a two‐electrode rf sputtering system, both electrodes are bombarded. In both sputter deposition and sputter etching this bombardment must be controlled for control of contamination and film properties. The ratio of ion bombardment energies at the two electrodes has been studied here by an indirect method using measurements of the rf and induced dc voltages between the electrodes. The behavior of this voltage ratio, and of the corresponding ion energy ratio, has been studied as a function of the electrode area ratio (varied between 0.3 and 1), the electrode material (SiO2 and stainless steel), the rf voltage on the electrodes (varied from 300 to 2000 Vpp), the gas (He, Ne, Ar, Xe, and CF4), and its pressure (from 0.1 to 100 Pa). The results show that while it is easy to obtain roughly equal ion bombardment of the rf electrodes, large ion bombardment energy ratios are difficult to obtain and require careful system design. ...

Apparatus for and method of controlling sputter coating

Abstract: The magnetic field of a magnetron sputter coating apparatus is controlled in response to measurements of plasma parameters to control deposition parameters, such as sputter deposition rate and material deposition thickness profile. From time to time the apparatus is standardized to change preset values for parameters of the plasma to manage the deposition parameters.

A sputtering cathode apparatus

Abstract: A sputtering cathode apparatus for the deposition of thin films which are produced at a relatively high deposition rate. A relatively large planar magnetron sputtering system or apparatus is provided with a preferred single convoluted electron path so as to obtain high geometric efficiency. The target is larger than the substrate and the substrate motion is confined to an area within the defined target area. The cathode system requires a vacuum system of relatively small dimension due to the increase in target size in comparison with substrate size along with the provision for multiple plasma legs separated by non-emissive regions therebetween. This construction enables minimized substrate motion relative to the target.

The current‐voltage characteristic of magnetron sputtering systems

Abstract: The I‐V characteristic of dc and rf magnetron sputtering systems has been shown to fit an expression of the form I=β(V−V0)2, where V0 is the minimum voltage necessary to maintain a discharge. New experimental data is presented for a dc planar magnetron with Al, Cd2Sn, Cr, and CdSe targets in argon discharges and for a dc Research S‐gun with an Al target in argon and argon/oxygen discharges. Literature data for planar, S‐gun, and cylindrical magnetrons has also been shown to fit the above expression; for rf magnetrons, I is the rms current and V is the target self‐bias voltage. V0 decreases from about 400 V at 0.1 Pa to 250 V at 1 Pa and then decreases at higher pressures. β increases from about 50 to ≤300 A/kV2 as the pressure increases from 0.1 to 10 Pa. The actual values of V0 and β depend on the system, target, and sputtering gas. It is shown that the I∝V2 dependence is due to a space‐charge‐limited electron current in the magnetron geometry which reduces the electron mobility by several orders of magn...

Reactively rf magnetron sputtered AlN films as gate dielectric

Abstract: AlN films were deposited on silicon (100, 111), fused quartz and GaAs (100) by sputtering in an Ar:N2 gas mixture. We report on the physical and chemical analysis of the films with the aid of scanning electron microscopy, x‐ray diffraction, and Auger electron spectroscopy. The films were found to be transparent with a c‐axis orientation. Their bulk resistivity was 1015 Ω‐cm. Quasistatic C‐V analysis of Al/AlN/Si gave a flat‐band voltage of 0.85 V, density of fixed charge of 6×1010 cm−2 and a density of fast interface charge of 1.5×1011 cm−2 eV−1 at midgap. These films were formed at 250 °C and offer an attractive fabrication alternative for gate dielectric.

Apparatus and process for sputter deposition of reacted thin films

Abstract: A method and apparatus for forming a thin film on a substrate by sputtering of a material from a cathode, which material is subsequently reacted to form the thin film. A process chamber has a sputter zone which contains a sputter electrode assembly and in which an inert sputtering atmosphere is injected. Isolation means separates the sputtering zone from a reaction zone of the process chamber, into which a chemically reactive atmosphere is injected, and prevents the chemically reactive atmosphere from entering the sputtering zone. A substrate receives a sputtered material in the sputtering zone, and is subsequently transferred to the reaction zone where the sputtered material is contacted by and reacts with the chemically reactive atmosphere therein to form a reacted thin film.

High photoconductivity in magnetron sputtered amorphous hydrogenated germanium films

Abstract: Undoped amorphous hydrogenated germanium films which exhibit photoconductivities greater than 10−6 (Ω cm)−1 at a 1.96‐eV photon flux of 1015 photons/(cm2 s) with corresponding mobility lifetime products of 10−6 cm2/V have been grown by magnetron sputtering. The films were also characterized by measuring the infrared absorption, the optical obsorption, and the dark conductivity as a function of temperature.

Magnetron sputter coating source for both magnetic and non magnetic target materials

Abstract: A novel magnetron sputter coating source is disclosed in which magnetic sputter targets containing relatively large inventories of usable material may be employed. This coating source may also be used efficiently and effectively with sputter target materials having properties which range from nonmagnetic to highly ferromagnetic. Use of an electromagnetic coil with a widely adjustable energizing current, rather than permanent magnets, allows a wide range of magnetic properties to be accommodated. Electrical impedance of the glow discharge is readily controlled using the current flow through the electromagnetic coil, allowing, for example, operation at desired values of voltage and current throughout the life of the sputter target. In addition, a momentary increase in electromagnet coil current can be used to achieve ignition of the glow discharge at a desired sputter gas operating pressure which is below the sputter gas pressure at which the glow discharge can normally be readily ignited. Also, use of the electromagnetic coil permits an easy conversion of the magnetron sputter coating source to a nonmagnetic diode apparatus. The use of a Hall probe positioned adjacent and below the sputter target near the region of maximum erosion is disclosed. The Hall probe voltage, which is proportional to the magnetic field intensity at the Hall probe position, may be measured throughout sputter target life to provide an independent means of assessing the approach to end of useful life. A novel sputter target cooling means is disclosed in which a water chamber below the sputter target is divided into inlet and outlet portions by a septum. The flow of water through a narrow gap between the septum and the sputter target leads to highly effective heat transfer, which is also highly uniform along the peripheral path of intense heating of the sputter target.

Chemical Vapor Deposition of PbTiO3Thin Film

Abstract: A PbTiO3 thin film has been grown on Pt or Pt-coated Si wafer by chemical vapor deposition instead of rf sputtering which makes a surface of substrate damaged. As the source material of the deposition, two kinds of combinations of (PbCl2 and TiCl4) and (PbO and Ti(C4H9O)4) have been tried to know the effect of chlorine inclusion in the PbTiO3 network. The surface of the film is much smoother than that of the film prepared by the rf sputtering, and deposition rate is several µm/hr. The deposited film structure is mostly oriented to or direction which depends on the source material and the deposition condition. The maximum dielectric constant of the film is 130, and D-E hysteresis characteristic has been also obtained.

Thin film deposition by sputtering

Abstract: The deposition of thin films is carried out by a co-sputtering cathode technique particularly suited for deposition of doped thin films on large area substrates. A relatively large planar magnetron sputtering apparatus having a rectangular (picture frame shaped) plasma region is provided to obtain efficient sputtering of the host material. A vacant center area defined by the plasma region is provided for diode sputtering of the dopant. In RF sputtering, co-excitation of the power source is desired to prevent RF mode beating.

Ion Beam Sputter Deposition Of Optical Coatings

Abstract: A beam of 500 to 1200 eV argon and oxygen ions, neutralized with an equal number of electrons, strikes a target, and the sputtered particles form a deposited layer of SiO2, Ta205, or TiO2. A second beam at lower energy is aimed at the substrate and used for stress modification and predeposition sputter cleaning. Deposited films are mechanically stable and extremely adherent; internal stress is compressive. The primary contaminant is carbon, which is less than one percent. Refractive indices near 1 µm are 1.47 for SiO2, 2.03 for Ta205, and 2.27 for Ti02. Optical absorptance of half-wavelength films at 1.06 Am is near 10-4 for SiO2 and Ta205 and near 4 X 10-4 for TiO2. Damage tests with a 114 um radius, 5 ns pulse length, 1.06 um wavelength laser show an onset energy flux for visible damage in the 12 to 30 J/cm2 range for single-layer films, and slightly less for a three-layer structure.