• Antifuse Technology based on Tetrahedral Amorphous Carbon
• Two Terminal Memory Device (RAM) of low Volatility
• Low Friction Wear Resistant Carbon Coating
• New Materials for Packaging
  

> Antifuse Technology based on Tetrahedral Amorphous Carbon

Antifuse devices are ideal for forming the programmable elements in field programmable gate arrays (FPGAs). FPGAS are finding an important place in a competitive chip market as they enable one chip design to perform a vast array of functions. A field programming device is used to select the desired functionality by forming connections between conductive lines. Antifuse has advantages of low capacitance connections and hence high speed. In antifuse, a connection is formed by fusing a link through an insulator using a programming current. Successful antifuse relies on having a high resistance before breakdown and a low resistance, permanent connection after breakdown. The device, once programmed must be totally reliable and not show any on-off switching. We have developed an antifuas structure which is the most reliable of all the antifuse structures we have tested as it has a thermodynamic advantage. We convert tetrahedral amorphous carbon, ta-C a diamond bonded form of carbon and metastable at room temperature into a conductive, thermodynamically stable form of amorphous carbon. We have published the performance characteristics in several papers and have a provisional patent application. We are looking for a commercial partner to develop the technology for the marketplace.

> Two Terminal Memory Device (RAM) of low Volatility

We have developed a low cost, low volatility random access memory with some advantages over other types of memory. The characteristics are

• The device relies on a two state conductivity phenomenon in amorphous carbon doped with nitrogen.
• The device has a low volatility and is able to retain a discrimination between the high and low conductivity states for periods of some months.
• The memory does show some fatigue phenomena for large numbers of cycles (approaching one million) when operated as a read/write memory.
• The device shows no fatigue as a read only memory.

This device consists of a simple MIM structure and should have low cost and high density. Because of its low volatility it could be used as a low refresh rate DRAM of very low energy dissipation.

We have developed a considerable depth of understanding of the mechanism for the two state conductivity. It is based on a Poole Frenkel emission mechanism from states associated with the nitrogen atoms. A structural alteration of the local region around the nitrogen atom has been shown to occur in ab initio molecular dynamics simulations. We are looking for a commercial partner to develop this device further. We can offer some patent coverage to assist the commercialisation.

> Low Friction Wear Resistant Carbon Coating

We have developed a form of carbon coating with exceptional low friction and wear resistant properties. The coating is deposited using cathodic arc deposition and simultaneous pulse biasing of the substrate. The carbon coating has very low intrinsic stress levels enabling is to be deposited to very large thicknesses, up to 14mm so far. In addition we have carried out extensive testing using pin on disc methods. We are currently using the coating in an implantable blood pump under development with our commercial partner Ventrassist. The coating is covered by a personal patent application as it is available for licensing for other applications.

> New Materials for Packaging

We have developed a new transparent material for improving the preservation characteristics of polymer packaging. Application of the coating to the polymers commonly used to wrap foods such as biscuits we have found, preserves the transparency while drastically reducing the permeability to water vapour. This process is applicable to a wide variety of polymers and is now ready for commercialisation.

For more information about any of the above, please contact Prof. David McKenzie.