Thin Film Diamond-Like Carbon Dielectrics

Richard L.C. Wu and J. D. Wrbanek

K Systems Corporation

1522 Marsetta Drive, Beavercreek, Ohio 45432

Tel: (937)-429-5151, Fax: (937)-429-1122

E-mail: rlwu@aol.com

M. Freeman

DARPA TACTICAL Technology

3701 North Fairfax Drive

Arlington, VA

Tel: (301) 394-5501, E-mail: mfreeman@darpa.com

S. Fries-Carr and J. Weimer

Air Force Research Laboratories

Wright-Patterson AFB, Dayton, Ohio 45433-6563

Tel: (937)-255-6016, Fax: (937)-255-3211

E-mail: sandra.fries-carr@afrl.af.mil

Abstract

Capacitors are a key and pervasive technology in every military and commercial application. Millions are used in military and commercial systems and are considered a critical link and a common area of failure. Capacitors often fail due to increasing environmental temperatures and low reliability, which may be due to low voltage breakdown strengths, high dissipation factors and problems associated with drift of the dielectric constant. Increased performance and smaller size have been the main focus of research in diamond-like carbon dielectrics for the application of high energy density capacitors. The viability of future military systems will rely on the development of pulse power, high energy density capacitors. These devices will be the enabling technology. Diamond Like Carbon (DLC) possesses the unique properties of high dielectric strength, high resistivity, low loss, high decomposition temperature, chemical inertness, radiation hardness and good thermal conductivity. It has been demonstrated that very thin (0.5 mm) DLC films can be deposited directly onto smooth aluminum surfaces with good adhesion and that amorphous DLC films are highly flexible, making them suitable for the production of wound capacitor devices. These DLC capacitors are an enabling technology for the More Electric Aircraft (MEA), Directed Energy Weapons (DEW), DE ATAC, UCAV, and High Power Microwave (HPM) demonstration programs. The military will also benefit from DLC Capacitors in Electronic Propulsion Power Conditioning, Space Based Laser (SBL) and Space Plane PMAD. If the technology can be fully commercialized, large pulse power capacitors can be reduced by more than 50% in weight and volume, and with substantial increases in electrical and thermal performance.

In this paper, we will describe a new manufacturing technology for producing high energy density DLC capacitors and properties of the resulting film. A unique dual ion-beam DLC deposition system has been designed, developed and constructed. The highly efficient hydrocarbon ions were produced by two 6 cm x 22 cm linear RF (13.56 MHz) inductively coupled ion guns. The DLC films are directly deposited on the both sides of thin capacitor grade aluminum foil in a continuous feed mode. The high energy density capacitors were then produced by rolling pairs of DLC-coated aluminum foils in a winding system. The dual ion gun system and the rolling system are housed in a class 100 clean room environment. A detailed discussion of the manufacturing technology and the voltage breakdown characteristics, as well as other electrical properties, of DLC dielectrics will be presented.

Keywords: Diamond-like carbon, pulsed power, high energy density capacitors, dual ion beam system

The corresponding author: Richard L.C. Wu, K Systems Corporation,1522 Marsetta Drive, Beavercreek, Ohio 45432,Tel: (937)-429-5151, Fax: (937)-429-1122,E-mail: rlwu@aol.com