Showing papers on "Chemical vapor deposition published in 1979"

Thin Film Processes

Abstract: J.L. Vossen and W. Kern, Introduction. S.M. Rossnagel, Glow Discharge Plasma and Sources for Etching and Deposition. C.V. Deshpandey and R.F. Bunshah, Evaporation Processes. P.P. Chow, Molecular Beam Epitaxy. R. Parsons, Sputter Deposition Processes. P.C. Johnson, The Cathodic Arc Plasma Deposition of Thin Films. K.F. Jensen and W. Kern, Thermal Chemical Vapor Deposition. K.F. Jensen and T. Kuech, Metal-Organic Chemical Vapor Deposition. J.G. Eden, Photochemical Vapor Deposition. L.C. Klein, Sol-Gel Coatings. R. Reif and W. Kern, Plasma-Enhanced Chemical Vapor Deposition. G. Lucovsky, D.V. Tsu, R.A. Rudder, and R.J. Markunas, Formation of Inorganic Films by Remote Plasma-Enhanced Chemical-Vapor Deposition. T.M. Mayer and S.D. Allen, Selected Area Processing. H.W. Lehman, Plasma-Assisted Etching. P.R. Puckett, S.L. Michel, and W.E. Hughes, Ion Beam Etching. C.I.H. Ashby, Laser-Driven Etching.

Antireflective coatings applied from metal–organic derived liquid precursors

Abstract: Antireflective (AR) coatings, which are produced from organometallic driven solutions containing oxide constituents in a chemically polymerized form, are presented. These solutions leave a film on substrates which, upon heat treatment, converts to a glasslike oxide film having the desired optical thickness and index of refraction. The index can be varied continuously from 1.4 to 2.4; thus the AR coatings can be fine-tuned for different substrates and for specific wavelengths of light. Silicon solar cells AR-coated by this technique showed as much as 49% improvement in efficiency over the uncoated state. The real advantage of the process, however, lies in the fact that it is simple, well-suited for automated mass production of photovoltaic cells, and reduces the cost of coating application from an estimated $0.20 per W-package to about $0.01 per W-package.

Kinetics of decomposition of amorphous hydrogenated silicon films

Abstract: The decomposition kinetics of amorphous hydrogenated silicon films have been studied by thermomanometric analysis at constant heating rate. rf and dc‐biased rf glow‐discharge films, as well as films deposited by reactive sputtering, have been analyzed and the results used to determine the thermodynamic parameters characterizing the activation barriers for decomposition of the =SiH2 and ≡SiH centers. Conclusions regarding the structure of these films are presented on the basis of kinetic evidence and parallel infrared absorption studies.

cw laser recrystallization of 〈100〉 Si on amorphous substrates

Abstract: A polycrystalline silicon film 0.55 μm thick was deposited in a low‐pressure CVD reactor on a Si3N4 substrate. Islands of various sizes (2×20 μm up to 20×160 μm) were prepared by standard photolithographic techniques. Laser annealing was then performed under conditions which are known to cause an increase in grain size from ∼500 A to long narrow crystals of 2×25 μm in a continuous polysilicon film. These same conditions were found to produce single‐crystal 〈100〉 material in the (2×20 μm) islands. However, 25×25‐μm and 20×160‐μm islands remain polycrystalline after the laser scan.

Laser‐induced vapor deposition of silicon

Abstract: Silicon films were deposited when silane was irradiated with a pulsed CO2 laser. This laser‐induced vapor deposition occurs effectively when the laser is tuned to an absorption frequency of SiH4. Efficiency was so high that an unfocused beam of 1.3 MW/cm2 sufficed. Any thermal effects are ruled out. Deposition is induced efficiently at gas pressures above 100 Torr, indicating that a collision‐aided process is involved.

Preparation and properties of Ga 1-x Al x As-GaAs heterostructure lasers grown by metalorganic chemical vapor deposition

Abstract: Recently Ga 1-x Al x As-GaAs double-heterostructure lasers having low threshold current densities have been grown by metalorganic chemical vapor deposition. In addition to these conventional double-heterostructure lasers, unique laser structures have been grown, e.g., channel-guide, distributed-Bragg-confinement, and single- and multiple-quantum-well lasers. We describe here the preparation and performance of these devices.

Optical properties of single‐crystalline ZnO film smoothly chemical‐vapor deposited on intermediately sputtered thin ZnO film on sapphire

Abstract: ZnO‐Br2‐O2, ZnCl2‐O2, and ZnO‐H2‐H2O‐O2 chemical‐vapor‐deposition (CVD) systems are studied to obtain as‐grown optical waveguides of single‐crystalline ZnO on sapphire. The waveguide is made on a very thin sputter‐deposited epitaxial layer of ZnO on sapphire by using the ZnO‐H2‐H2O‐O2 isothermal CVD system. The minimum loss obtained for the TE0 mode propagating perpendicular to the c axis in a (1120) ZnO film is 0.7 dB/cm. This chemical‐vapor deposition of ZnO on a thin‐sputtered ZnO film gives a method for the fabrication of strip waveguides on sapphire due to the selective growth of the ZnO films on sputter‐deposited ZnO strips.

Low-pressure chemical vapor deposition for very large-scale integration processing—A review

Abstract: An overview is presented of low-pressure chemical vapor deposition and its applicability to VLSI processing for depositing thin films of insulators, semiconductors, and metals. The major contributions of low-pressure chemical vapor deposition to VLSI technology are its capability for economically producing films with superior uniformity, high purity, and excellent step coverage-factors essential for achieving the very high device reliability and high product yield required in the manufacturing of VLSI devices. Specific examples from the recent literature are reviewed to exemplify how the technique has been utilized to date in solid-state device technology. Applications of films produced by low-pressure reactive plasma chemical vapor deposition are also included.

Continuous 300 °K laser operation of single‐quantum‐well AlxGa1−xAs‐GaAs heterostructure diodes grown by metalorganic chemical vapor deposition

Abstract: Stripe‐geometry single‐quantum‐well AlxGa1−xAs‐GaAs double‐heterostructure laser diodes (Lz∼200 A) grown by metalorganic chemical vapor deposition are shown to operate continuously at 300 °K on the first (n=1) electron–to–heavy–hole (e→hh) or first (n′=1′) electron–to–light–hole (e→lh) confined‐particle transitions (h/ω−Eg∼11 meV). These laser diodes exhibit an external differential quantum efficiency as high as ηext∼80% (output power 5.4 mW at 65 mA drive current).

Characterization of improved InSb interfaces

Abstract: Improved quality surfaces on n‐type InSb have been produced using a low‐temperature chemical vapor deposition (LTCVD) of SiO2 by pyrolytic decomposition of silane in the presence of oxygen. Preservation of the thin, natural oxide on the InSb surface through a suitable LTCVD process results in a surface state density ≳1010 eV−1 cm−2 and without C–V hysteresis. Confirmation of these results is made by both quasistatic C–V and conductance measurements on MIS structures. Complications introduced by the presence of lateral nonuniformity of the LTCVD oxide and thus in the surface potential, have been accounted for in the observed low density measurements. The presence, chemical identification, and thickness of the natural oxide, both before and after the LTCVD process, has been idependently confirmed by XPS. The apparent oxidation state and resultant electrical properties are identified with changes in LTCVD reactor conditions.

The chemical vapor deposition of TiB2 on graphite

Abstract: In this paper we describe an experimental investigation of the coating of graphite with TiB 2 by chemical vapor deposition using the H 2 reduction of BCl 3 and TiCl 4 at 925 °C and 1 atm. Reasonable matching of the thermal expansion of TiB 2 and graphite was necessary to eliminate cracking. A suitable graphite was POCO DFP-1. Adhesion was improved by using a slightly rough graphite surface. Heat treatment at 2000 °C and above resulted in a certain degree of diffusion. No melting or solid phases other than TiB 2 and graphite were detected up to 2400 °C. The coatings showed no failure when repeatedly submitted to an electron beam pulse of 2 kW cm −2 for 0.8 s.

Al0.5Ga0.5As‐GaAs heterojunction phototransistors grown by metalorganic chemical vapor deposition

Abstract: Al0.5Ga0.5As/GaAs heterojunction phototransistors have been fabricated from structures grown by the MO‐CVD process. The relatively high optical gains (∼100) and short response times (≲2 nsec) obtained with these devices indicate that an optimized AlxGa1−xAs/GaAs heterostructure phototransistor could be a suitable detector for optical‐fiber‐communication systems using GaAs DH lasers.

Hydrogen concentration profiles and chemical bonding in silicon nitride

Abstract: The complementary techniques of nuclear reaction analysis and infrared absorption were used to study the concentration profiles and chemical bonding of hydrogen in silicon nitride for different preparation and annealing conditions. Silicon nitride prepared by chemical vapor deposition from ammonia-silane mixtures is shown to have hydrogen concentrations of 8.1 and 6.5 at.% for deposition temperatures of 750 and 900‡C, respectively. Plasma deposition at 300‡C from these gases result in hydrogen concentrations of ~22 at.%. Comparison of nuclear reaction analysis and infrared absorption measurements after isothermal annealing shows that all of the hydrogen retained in the films remains bonded to either silicon or nitrogen and that hydrogen release from the material on annealing is governed by various trap energies involving at least one Si-H and two N-H traps. Reasonable estimates of the hydrogen release rates can be made from the effective diffusion coefficient obtained from measurements of the spreading of the implanted hydrogen distribution upon annealing.

Simultaneous RHEED AES QMS study on epitaxial Si film growth on Si(111) and sapphire (1̄102) surfaces by partially ionized vapour deposition

Abstract: The role of simultaneous measurements of the chemical composition of a surface by AES, surface crystalline structure by RHEED, and released species by QMS are presented. A molecular beam of Si is effused from a partially ionized vapor deposition (PIVD) source consisting of a Kundsen cell and an electron‐impact‐type ionization chamber. The 7×7 structure of a Si(111) substrate at 1100 K changes into a broad 1×1 structure after vacuum deposition (VD) of 15 nm of Si while the epitaxial temperature can be lowered to 620 K (PIVD) in a 0.5% ionized atomic vapor with a typical deposition rate and acceleration energy of 0.3 nm/min and 100 eV, respectively. Epitaxial growth of Si on sapphire (1102) can be observed at 850 (VD) and at 700 K(PIVD), with a 1% ionized atomic vapor. The Auger spectra during deposition at 870 K remarkably shows that O and Al are reacted with Si on the film.

Specifications Of Raytran Material

Abstract: RAYTRAN infrared materials are formed by the chemical vapor deposition process which produces materials of unique characteristics and properties. This specification establishes optical and physical property requirements for polycrystalline zinc selenide and zinc sulfide made by this process.

The influence of plasma annealing on electrical properties of polycrystalline Si

Abstract: Polycrystalline silicon doped with phosphorus and boron was prepared by low‐temperature CVD and was annealed in a hydrogen/nitrogen plasma at 300 °C. The dopants were introduced by ion implantation and the concentration ranged from 2×1016 to 2×1019 cm−3. Plasma annealing decreased the poly‐Si resistivity, which is significant at particular doping concentrations depending on density of localized states. The effect is due to reduction of deep localized states through hydrogenation and is canceled by additional annealing in nitrogen at 600 °C.

Abrupt Ga1−xAlxAs‐GaAs quantum‐well heterostructures grown by metalorganic chemical vapor deposition

Abstract: Multiple‐quantum‐well Ga1−xAlxAs‐GaAs heterostructures grown by metalorganic chemical vapor deposition have been analyzed by Auger electron spectroscopy combined with simultaneous argon‐ion sputter etching The chemical‐interface widths of the Ga045Al055As‐GaAs heterojunctions are determined to be ≲17 A In addition, no Al is detected in the GaAs quantum wells

Low pressure chemical vapor deposition of silicon dioxide with oxygen enhancement of the chlorosilane-nitrous oxide reaction

Abstract: A method is described for forming a silicon dioxide layer on a semiconductor substrate in a furnace heated reaction zone of a chemical vapor deposition reactor having an input end for gaseous reactants wherein the silicon dioxide layer is not subject to degradation during subsequent oxidation cycles. A gaseous chlorosilane is mixed with nitrous oxide gas in the reactor. Oxygen gas is added, between about 0.25% to 10% by volume of total reactive gas mixture, to the chlorosilane and nitrous oxide gases in the reaction zone where the temperature is between about 800° C. to 1200° C. in a pressure of less than about 5 torr to deposit the silicon dioxide layer onto the substrate.

Continuous room‐temperature multiple‐quantum‐well AlxGa1−xAs‐GaAs injection lasers grown by metalorganic chemical vapor deposition

Abstract: Room‐temperature (∼26 °C) continous operation of AlxGa1−xAs‐GaAs multiple‐quantum‐well injection lasers has been achieved. These devices are grown by metalorganic chemical vapor deposition and employ active regions consisting of six GaAs quantum wells having a thickness Lz∼120 A separated by five Al0.30Ga0.70As barriers also ∼120 A thick. These laser diodes operate on LO‐phonon‐assisted confined‐particle transitions and exhibit low threshold current densities (Jth∼1660 A/cm2) and high total external differential quantum efficiencies (ηext∼85%).

Enhanced ARE apparatus and TiN synthesis

Abstract: To apply the activated reactive evaporation (ARE) process to coatings for telecommunication components, the deposition rate must be less than 0.1 μm/min. To accomplish this slow rate, an electron emitting electrode was attached to the ARE apparatus. Electrons emitted from the electrode ’’enhanced’’ the ARE process. In the enhanced ARE process, the generation of plasma and evaporation of metal can be controlled independently. Therefore, the deposition rate can be controlled widely, and resistance heating and laser heating can be used for evaporation instead of electron beam heating. The enhanced ARE process was tested by synthesizing titanium nitride. Since N2 gas pressure can be varied widely in the enhanced ARE process, the chemical composition of the Ti–N films is more easily controlled than with the ARE process. Ti2N film synthesized by the enhanced ARE process showed a maximum hardness of Hv:2824 kg/mm2.

7.3% Efficient thin-film, polycrystalline n-GaAs semiconductor liquid junction solar cell [14]

Abstract: By elimination of grain boundary effects, it is possible to approach single-crystal efficiency provided that the mobility remains high and an optimal, uniform doping level is maintained throughout the grains. Such a situation is approached in thin-film, chemically vapor deposited n-GaAs, following exposure to a Ru(III) solution. The anode used was n-GaAs/n/sup +/-GaAs/W/graphite. A 24-..mu..m thick layer of n-GaAs was deposited on a 2 to 3-..mu..m tungsten-on-POCO graphite substrate by the reaction by hydrogen chloride, gallium, and arsine at 775/sup 0/C. The grains were of 1 to 20 ..mu..m diameter, with an average linear dimension of 9 ..mu..m. The measurements were done under 96.4 mW/cm/sup 2/ incident sunlight. The insolation was determined by an Eppley Model PSP radiometer, which measures the direct and scattered insolation from the entire sky. This demonstrates that grain-boundary diffusion of a strongly bound impurity can reduce the grain-boundary-related losses in solar cells made with thin-film polycrystalline semiconductors. This work suggests that it is possible to approach more closely single-crystal efficiencies in thin-film polycrystalline solar cells than originally thought. 2 figures. (DP)

Bevel cross sectioning of ultra-thin (∼ 100 Å) III–V semiconductor layers

Abstract: A method is described for extending the use of bevel cross sectioning of semiconductor layers from the usual limits of 500–1000 to 80–100 A. The modified bevel cross sectioning described is used to view the 11 layers (6 GaAs and 5 AlGaAs, each ∼ 120 A) and the 7 layers (4 GaAs and 3 AlGaAs, each ∼ 80 A) of two multiple quantum-well AlxGa1−xAsGaAs (laser) heterostructures grown by metalorganic chemical vapor deposition (MO-CVD).