Conference 7.286::space

283.0. "Space Diamonds" by EDEN::KLAES (Patience, and shuffle the cards.) Wed Apr 22 1987 16:35

VNS TECHNOLOGY WATCH:                           [Mike Taylor, VNS Correspondent]
=====================                           [Nashua, NH, USA               ]

                 Diamonds Find New Settings 
    
    Industrial researchers have long known that there's much more to
    diamonds than good looks.  Besides being the hardest substance
    known, diamond also exhibits a remarkable set of physical,
    chemical, and electrical properties; it is unmatched in
    transparency, for example, is an efficient conductor of heat and
    electricity, and is highly resistant to corrosion and radiation. 
    
    Now researchers in the US, Japan, and the Soviet Union are
    trying to put these properties to work in the from of ultrathin
    diamond films.  Although most of the the work is still in the
    precommerical stage, materials specialists say the near term
    results could include sharper and more durable data storage
    disks; eventually, the technology could also lead to powerful
    new transistors and higher density computer chips. 
    
    The optimism arises from recent experiments at Pennsylvania
    State University, where researchers have duplicated diamond
    coatings first de in Japan and the Soviet Union.  In the Penn
    State technique, the object to be coated is exposed in a quartz
    tube to a plasma formed by exposing methane gas, hydrogen, and
    argon to intense microwave radiation.  Within an hour, the carbon
    atoms in the methane plate out as a diamond layer about one or
    two millionths of an inch thick. 
    
    Until recently, only a few American researchers had tried to
    make the ultrathin films.  They labored for years but had been
    unable to produce coatings with all the properties of diamonds.
    US scientists were thus skeptical about reports during the 1970s
    that investigators at Moscow's Institute of Physical Chemistry
    had made true diamond films via chemical vapor deposited (CVD)
    on a substrate. 
    
    Diamond Semiconductors? Research is also under way to tap the
    electrical characteristics of diamond films. For example,
    transistors made of diamonds films, unlike conventional silicon
    based devices, could handle high power signals at the microwave
    frequencies used in earth to satellite links.  The Defense
    Department is also interested because diamond transistors are
    practically invulnerable to the nuclear radiation that might be
    encountered in "Star Wars" type scenarios.  Another military
    application in the works is diamond power transistor for
    generating intense ultraviolet laser beams that could aid in
    satellite to satellite communications, or be harnessed to
    destroy enemy missiles. Diamond based semiconductors could also
    be fabricated into ultraviolet detectors for civilian and space
    communications. And diamond coated electronic sensors for
    automobile engines, under study by several Japanese companies,
    could function reliably in some of the hottest parts of the
    engine, for example next to the combustion camber to monitor gas
    composition. 
    
    One of the most sought goals of diamond researchers is an
    integrated circuit made of diamond rather than silicon. Since
    diamond's thermal conductivity is at least 10 times that of
    silicon, diamond semiconductors could (at least in theory) be
    placed closer together, allowing for perhaps an order of
    magnitude increase in circuit density over conventional devices. 
    
    Japan's Sumitomo Electric Industries reportedly has grown
    semiconductor diamond films and will begin to marketing devices
    for space and automotive applications within the year.  Several
    sources familiar with Sumitomo's work say the company's diamond
    films have been grown on other diamonds (instead of more
    economical metals and other materials), as a result the
    company's devices will likely cost more than ordinary silicon
    based chips.

    {High Technology April 1987}

  <><><><><><><>   VNS Edition : 1303   Wednesday 22-Apr-1987   <><><><><><><>

VNS TECHNOLOGY WATCH:                           [Mike Taylor, VNS Correspondent]
=====================                           [Nashua, NH, USA               ]

                           Diamond in the Rough

    Man made diamonds could offer a solution for space based electronics
    say scientists at the Research Triangle Institute.  The RTI
    researchers already can "deposit electronics grade diamond on
    on-diamond substrates," says the VP for electronics and systems at
    RTI.  But a suitable substrate is still to be found.  A nickel copper
    alloy seems the best so far, but it still could years to design a
    substrate with electrothermal characteristics similar to the active
    diamond layer.  "Diamond is a high band gap material.  It has a high
    thermal conductivity, high electron mobility, high resistance to
    radiation, and very high breakdown voltage."

      {Electronic Design Feb 23, 1989}

  <><><><><><><>   VNS Edition : 1775     Tuesday 14-Mar-1989   <><><><><><><>