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Sputtered Films of Cubic Boron Nitride

IP.com Disclosure Number: IPCOM000109086D
Original Publication Date: 1992-Jul-01
Included in the Prior Art Database: 2005-Mar-23
Document File: 2 page(s) / 90K

Publishing Venue

IBM

Related People

Gambino, RJ: AUTHOR [+4]

Abstract

Disclosed is a sputtering process that produces stable, thin films of cubic boron nitride (BN). Uniform coatings of hard materials, such as diamond and cubic BN, are needed for wear resistance and a low coefficient of friction in many applications such as magnetic disks and heads.

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Sputtered Films of Cubic Boron Nitride

       Disclosed is a sputtering process that produces stable,
thin films of cubic boron nitride (BN).  Uniform coatings of hard
materials, such as diamond and cubic BN, are needed for wear
resistance and a low coefficient of friction in many applications
such as magnetic disks and heads.

      Opposing target sputtering is a deposition method which gives
high rates while avoiding bombardment of the growing film by
energetic particles (1).  These particles can cause modification of
film structure.  Magnetron enhancement of the plasma makes it
possible to operate the sputtering system at high rates with gas
pressures in the mTorr range.  This means that the arriving flux is
not thermallized by collisions with gas molecules and retains the
kinetic energy imparted by the target (about 10 eV) resulting in an
arrival flux with moderate kinetic energy and few damaging highly
energetic particles.  This intermediate energy range has been found
to favor sp3 bonding in amorphous carbon (2).  Typical sputtering
conditions of 750 watts target power, 3 mTorr argon pressure and
200~C substrate temperatures formed transparent cubic BN films at 60
angstroms/minute on a variety of substrates.

      The apparatus used is shown in the figure.  The targets are
machined out of commercial hexagonal BN and are powered by the same
rg generator through a power splitter as shown.  The large negative
target potentials combined with the axial magnetic field serves to
confine the electrons to the plasma region where they produce many
more impact ionization events and give a more intense plasma.  The
substrates are supported on a ring surrounding the plasma and are not
heat sunk.  The plasma heat load causes the substrates to floa...