All posts by Charley Parker

Metallization

Applied Diamond has developed our metallization capabilities to suit the needs of high power applications.  Diamond metallization schemes usually involve three different metals. The first, closest to the diamond, is a carbide-former.  Titanium, tungsten or chromium are common examples. These metals make a chemical bond with the diamond to insure adhesion of the metallization. A diffusion-barrier may then be applied, typically palladium or platinum, to minimize alloying of the chemically active bonding layer with the final metal layer. Finally, the layer required for the process is added. Gold or silver are usually used to prepare the diamond for soldering, eutectic bonding, wire bonding or as electrical contacts.  Annealing, in air or vacuum, can then be done as needed.

Of course, these processes are easily applied where patterning is needed too.  Full wafers of parts can be patterned and laser diced with specialized processes to insure electrical isolation between pads and ground planes.  Processes like these are important whether the diamond is used as an active or passive device in electronic applications.

Our standard metallization scheme, useful for bonding devices to diamond heat spreaders, is:

Titanium – 1,000A
Platinum – 1,000A
Gold – 10,000A

We have extensive experience with a number of variations of this scheme including different adhesion and final layers, reflective layers and stacks of 5 or more layers.

We constantly solve new challenges in the metallization area.  If you have a need that requires some other type of metallization or concerns about your specific application, let us know.

Diamond Plates

Applied Diamond has 20 years of experience growing diamond plates of various qualities for an extensive variety of research and industrial applications.  The combination of diamond’s extreme hardness, thermal conductivity, chemical and pressure resistance, and electrical resistivity make it a unique material for experiments and applications in extremely difficult conditions. Diamond can do things that other materials just can’t.  Modern techniques have enabled us to make bespoke plates that meet the demands of any challenging situation.

We can provide diamond plates in four different qualities:

  • Optical Grade – highly thermally conductive, 1700-1800 w/mK
  • Electronic Grade – highly thermally conductive, 1700-1800 w/mK
  • Thermal Grade – opaque diamond, 900-1000 w/mK
  • Tool Grade – black diamond 700-800 w/mK

Thermal and Tool Grade, while not as conductive may still be ideal for your application and can be a more cost effective option.

Plates can be either single crystal or polycrystalline in type and we can polish and shape them to suit.  Circles and squares are the most common, but we have experience with exotic shapes and can apply edges if required.  Combined with our other capabilities, we can build custom diamond plates for almost any application.

Diamond Optics

Diamond has an exceptionally high transmission over a very broad range of wavelengths and low scatter in IR applications. It is extremely hard and chemically inert; making CVD diamond the optimal choice in applications demanding higher power, larger area, and resistance to hazardous materials or greater strength.  These abilities also enable smaller material geometries to be used, which opens up new lightweight applications.  Advances in the creation and shaping of diamond enable us to provide solutions to novel optical problems.

CVD Optical Transmission

Applied Diamond’s optical products are:

  • Available in both SC (up to 7.5 mm sq) and poly (up to 2” in diameter)— Thicknesses up to 1.2 mm
  • Surface roughness down to 2-3 nm Ra for SC and 10 nm Ra for poly
  • Wedged or flat—wedged for the suppression of interference oscillations. Wedge angle: 0.5 to 1 degree
  • Mounted in flange or free-standing
  • Cut in a variety of shapes and sizes, including lenses and prisms
  • Up to 30 mm free aperture for brazed windows—leak tight at better 1 x 10E-10 atm-cc/sec

Diamond’s exceptional properties provide benefits in a variety applications:

  • High power CO₂ lasers
  • Long wavelength IR imaging (8-14 micron)
  • Spectroscopy
  • High power RF generators and gyrotrons
  • Disc lasers
  • Raman lasers
  • VECSELs
  • Diamond lenses

Diamond Heat Spreaders

Applied Diamond can build heat spreaders for the most extreme possibilities.  As a material, diamond has no peer as a semiconductor medium.  The unsurpassed thermal conductivity of diamond and its high electrical resistivity allow for better performance across virtually all measures of semiconductor performance.  The ability of diamond to insulate high voltages across much thinner layers of material enables diamond to be used in lightweight applications.

Applied Diamond offers three thermal conductivities tailored to the cost/performance requirement of our customers:

  • Low – black diamond 700-800 w/mK
  • Medium – opaque diamond 900-1000 w/mK
  • High – optically clear diamond 1700-1800 w/mK for the most difficult heat problems

We can make spreaders with lithographically patterned metallization and electrically isolate top and bottom surfaces.

Metallization solutions include:

  • Titanium, Platinum and Gold
  • Titanium, Nickel Gold
  • Chrome, Gold

We can offer heat spreaders with the following characteristics:

  • Range of thicknesses available: up to 1mm thick
  • Very flat and low roughness ensuring ease of attachment and minimized thermal interface resistances
  • Diamond is grown on 2” wafers  that can be laser cut to any required size
  • Flat, smooth diamond with Metallization solutions enabling die bonding, standard soldering and brazing

Brazed Window Flange

Applied Diamond uses active brazes in a variety of vacuum apparatus for brazing diamond parts and shapes to holders of various designs. Brazing of diamond to other materials is always done in a vacuum or inert atmosphere to avoid oxidation.

Use vacuum brazing for:

  • Bonding single crystal or CVD diamond parts to tool shanks and inserts.  Brazing provides a very strong joint prior to edge finishing of tools.  The metallic filler material allows rapid transmission of heat from the cutting zone to the bulk of the shank and holder.
  • Vacuum-tight joints between diamond windows and vacuum fittings.  Filler metals are high vacuum compatible and allow what little energy that is absorbed by the diamond to be readily transmitted (as heat) to the flange which can be water-cooled.
  • CVD diamond film applied to tungsten carbide backing.  We can provide diamond tool blanks in a form that you can readily braze in air to tool steel shanks and sharpen in-house using your standard production equipment.
  • Diamond shapes sintered between powder metal blanks.  These purely mechanical bonds are useful for dressing, scribing and many other tool applications.

Vacuum brazing is just one more operation we can use to solve your difficult diamond applications.

Single Crystal and Polycrystalline Industrial Diamond for Technical and Research Applications

  • Natural and synthetic diamond products
  • In-house diamond synthesis by microwave plasma CVD process
  • Diamond in orientations of <110>, <111>, and <100>
  • HP/HT and polycrystalline or single crystal CVD materials
  • Wafers of specified thicknesses
  • Range of fabrication capabilities- polishing, metallization, etching, brazing
  • A full range of post-processing capabilities
  • Custom design and product development
  • Quick turnaround on prototypes
  • Stock on shelf for blanket orders
  • Telephone technical assistance