Diamond film Growth

Diamond films are available in a wide variety of geometries, purities, and properties.  Polycrystalline diamond films fall broadly into five grades: electronic, doped, optical, thermal, and mechanical.  While the cost of processing films into finished parts is independent of the film grade, the relative cost of such films is listed near its grade.  Optical grade films given an arbitrary value of 1.  All values are approximate and subject to change.

 

Mechanical grade diamond (Cost factor = 0.25)

Mechanical grade is typically black as a result of numerous inclusions due to its fast growth rate.  These inclusions make the material unsuitable for optical applications and degrade its thermal performance (~800 W/m-K), but have very little impact on the mechanical properties of diamond.  This fast growth rate facilitates this grade being the most cost effective, yet still superlative for applications where the hardness and tribological properties of diamond are of primary importance.  These films have found applications in low friction pads and cutting blades.

Read more about the mechanical properties of diamond.

 

Thermal grade diamond (Cost factor = 0.5)

Thermal grade is typically transparent but may be cloudy, have some brown color, and/or black inclusion spots not unlike looking though a dirty windshield.  These isolated defects have a minimal effect on thermal conductivity and are more cost effective than optical grade diamond.  These films may be deliberately accelerated in growth or may be rejected optical grade films that had a few too many inclusions.  Thermal grade diamond has a thermal conductivity of ~1500W/m-K.  

Read more about the thermal properties of diamond.

 

Optical grade diamond (Cost factor = 1)

Optical grade diamond is the high grade material that represents the ideal, bulk values for diamond as published in literature.  It has no trace of color and no inclusions visible to the naked eye.  These films find applications in optics, windows, and thermal applications that require the absolute best thermal conductivities available.

Read more about the optical properties of diamond.

 

Boron or Phosphorous doped diamond (Cost factor = 1.5)

Note: These grades are presently under development and not available for sale at this time.  If interested, please contact us to discuss your interest and receive an estimate of when this material will become available.  Enough interest will justify expediting development.

Doped diamond materials are interesting from two broad perspectives.  The first is a material with all the superlative properties of diamond PLUS electrical conductivity.  Electrochemistry, biomedical electrodes, and transparent conductive coatings all fall into this category.  The second is an interest in producing electronic devices such as P-N junctions in a diamond wafer.  

Read more about the chemical properties of diamond.

Read more about the electronic properties of diamond.

 

Electronic grade diamond (Cost factor 2.5)

Electronic grade is a label applied to material for which the electrically active impurity content of the diamond has been held to a minimum.  Typical nitrogen concentrations are of the order of 5 ppb.  Silicon and boron concentrations are historically below detectable limits.  This material is visually indistinguishable from optical grade, but cryogenic photoluminescence spectroscopy verifies extremely low impurity levels. Orders for this material are accompanied by characterization of the batch demonstrating such.

Read more about the electronic properties of diamond.

 

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