Advanced carbon technology is a key capability at the Center for Coatings and Laser Applications (CCL) Coating Technology Division. Working in partnership with Michigan State University, expertise includes CVD Diamond synthesis and PVD amorphous carbon (Diamond Like Carbon). In addition fully integrated services in relation to carbon-based materials synthesis and film deposition technologies are available to customers.

As part of its program to strengthen and integrate its carbon technology into customer applications, CCL is adding to its repertoire by acquiring new equipment and new expert resources. This enables the Center to further widen its services to customers.
CCL has also been actively promoting its carbon technology developments, most recently by participating at the Applied Diamond and NanoCarbon Conference and Exhibition which took place at Argonne National Laboratories, Argonne, IL in May 2005.

In terms of capability CCL has a broad spectrum of diamond synthesis know-how covering Diamond Like Carbon (DLC), Ultra-nano, Nano, Polycrsytalline and Single Crystal Diamond.
Equipment used at the facility includes both PVD and Microwave CVD systems ranging from 2.45 GHz to 915 MHz, enabling the deposition of carbon coatings and freestanding diamond material.

Deposition Systems:

• Fraunhofer PVD Laser-Arco® System (for deposition of DLC coating Diamor®)
• Five 2.45 GHz CVD systems (diamond deposition)
• 915 MHz CVD system (for large area diamond deposition)

Recent acquisitions include a Logitech diamond polishing and lapping machine and an ECR etching machine based on MSU plasma technology has been commissioned.
So in addition to the fabrication of diamond, CCL has established the necessary process technology to allow the development of products that incorporate diamond as an engineered material. For shaping, finishing, assembling and testing of carbon materials, processing capability now available at CCL includes polishing, lapping, etching cutting, characterization and services.

Shaping: Plasma etching, laser micromachining
Finishing: Plasma etching, lapping and polishing
Assembling and Testing: with industry collaboration e.g. foils, windows

In terms of resources, a welcome new addition to the team is Dr. Mikael Karlsson, formerly of Uppsala University in Sweden. Dr. Karlsson has an extensive background in diamond technology specializing in diamond etching processes and optical diamond applications. His experience and expertise will further enhance CCL's capability, enabling the Center to target new application areas and potential research collaborations.

The Applied Diamond Conference and Exhibition at Argonne, IL last month allowed CCL to showcase some of its developments in carbon technology. On display were freestanding diamond foils used as electron stripping foils for accelerator beams as well diamond coated Si wafers ranging in size from 75mm to 150mm.

In addition a poster was presented describing the innovative work on the measurement of thermal conductivity of thin diamond films that was carried out at the Center.
Knowing the thermal conductivity of a material is important for the successful design and implementation of any thermal management application. A special challenge however is the experimental determination of the thermal conductivity of highly thermal conductive materials such as diamond, which are synthesized in the form of thin films
For this work, CCL implemented the so-called 3ω method.
The experiment was designed to be able to measure the thermal conductivity of very thin films (a few micrometers) with thermal conductivities above 2,000 W/m·K (bulk conductivity of diamond).

The analysis and characterization measurements and techniques for carbon materials carried out at CCL include:

• Young's modulus
• Raman spectroscopy
• Thermal conductivity
• Roughness
• Wear volume/coefficient of friction (dry and lubricated)
• Adhesion
• Thermal and electrical transport (e.g. thermal conductivity)
• Thickness
• Optical and electron microscope
  

Applications for diamond and other carbon materials include:

• Diamond foils with a thickness from 1 to 50 µm
• High power laser and mm wave windows
• Diamond coated wafers
• Diamond coated atomic force microscope tips
• Conductive diamond coatings for electrochemical applications
• Electrodes and electrical contacts
• Diamond for MEMS devices
• Coatings for implantable biomedical applications and BioMEMS
• Diamond coated grids (e.g. for ion sources)

For more information, please contact cclinfo@fraunhofer.org