Directed Vapor Deposition: Low Vacuum Materials Processing Technology

Abstract

Directed vapor deposition (DVD) is a recently developed electron beam-based evaporation technology designed to enhance the creation of high performance thick and thin film coatings on small area surfaces (generally 100 cm 2 or less). DVD technology development has been driven by a desire to combine four processing capabilities into one industrially appealing system. These capabilities are: 1) very high rate deposition (5 µm/min and higher over a 100 cm 2 area), 2) very high material utilization efficiencies (on 100 cm 2 areas, efficiencies should at least triple that of other coating technologies), 3) precise control of growing film atomic structure, and 4) highly flexible definition of growing film atomic composition. These criteria have led to the development of a unique plasmaenhanced electron beam evaporation tool which will be described here. Initial experimental and modeling results will also be presented to demonstrate how the selected technology solution is allowing the desired processing features to be achieved.Keywords: directed vapor deposition, DVD, high rate evaporation, low vacuum materials processing, electron beam evaporation IntroductionFor many years vapor deposited coatings have been recognized as valuable components of numerous engineered consumer products. Such coatings are regularly incorporated into products to provide functionality unachievable through other means. Sometimes the coatings act as a barrier, e.g. environmental protection or surface wear resistance. In other instances they play roles as active components in the engineering system, e.g. converting the sun's energy to electricity or storing bits of computer information in magnetic domains. In all cases, introduction of the vapor deposited coating is motivated by some product specification which cannot be met through other means. Engineers recognize that each coating makes it possible to deliver the specified product with the required performance characteristics. At the same time, they know that use of the coating adds to the cost of the product. The competition between performance need and product cost drives the search for new vapor deposition technology which can provide desired performance at a lower market cost. Report Documentation Page Form Approved OMB No. 0704-0188Public reporting burden for the collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to a penalty for failing to comply with a collection of information ...

Development of alloy coatings by electron beam physical vapour deposition method

“…There are different methods used to increase the target's temperature during evaporation, such as resistive heating, electron and laser beam heating, arc and electrical induction heating [2,5].…”

“…(1) In the gas phase and vapour cloud due to electron collisions with vapour atoms, (2) In the evaporant material because of backscattering electrons, (3) At the surface of evaporant by converting into radiation energy, (4) By heat transfer through conduction into the crucible containing the evaporant target and (5) Collision of a fraction of electron beam with different parts of the electron beam gun [5].…”

Directed Vapor Deposition of a Cadmium Replacement Coating for High Strength Fasteners

“…It was initially developed at the University of Virginia and is licensed to DVTI, Inc. 7 . It provides the technical basis for a flexible, high quality coating process capable of atomistically depositing dense, compositionally controlled coatings onto line-of-sight and non line-of-sight (NLOS) regions of high strength fastener components.…”

Lithium phosphorous oxynitride films synthesized by a plasma-assisted directed vapor deposition approach

“…27 Thornton empirically showed that these conditions result in porous columnar-structured films. 30,35 Hollow cathode discharges have higher electron densities ͑in the ϳ10 12 cm −3 range͒ than those of a rf discharge ͑in the ϳ10 10 cm −3 range͒. [32][33][34] Morgner and co-workers have proposed a HAD process, which can be combined with high rate thermal evaporation DVD approach to enable the reactive synthesis of conductive and dielectric films with reduced intercolumnar porosity.…”

“…[32][33][34] Morgner and co-workers have proposed a HAD process, which can be combined with high rate thermal evaporation DVD approach to enable the reactive synthesis of conductive and dielectric films with reduced intercolumnar porosity. 30,[35][36][37][38][39] The low-voltage electrons have a high inelastic scattering cross section during collisions with argon and efficiently create an argon plasma. 30 The electron energy distribution function is composed of a Maxwell distribution of isotropically scattered electrons and a superimposed directed electron distribution-the so called low-voltage electron beam ͑LVEB͒ whose energy is in the 3 -15 eV range.…”