New routes to diamond nucleation, epitaxy and growth at low temperatures

This project aims to develop a new technique to initiate the growth of diamond on silicon. It is based on the chemical attachment of adamantane, the smallest diamond structured molecule available. This molecule will act as a seed for diamond growth, allowing the growth of very thin diamond films at previously unreachably low temperatures. It also offers the possibility of diamond epitaxy, i.e. the growth of single crystal diamond on silicon. This would offer a new source of high quality diamond for industry over large areas.

The global market for diamond and diamond-like coatings is expected to grow from an estimated $800 million in 2009 to almost $2 billion in 2015. The majority of these markets are dominated by polycrystalline diamond for heat spreading, optical, IR and microwave windows, tribology and electrodes for waste - water treatment (see www.e6.com and www.diamond-materials.com). Recent new markets include biosensors / biological applications, high temperature / high voltage / high frequency electronic devices (eg Diamond Microwave devices Ltd, based in Leeds), radiation detectors (eg Diamond Detectors Ltd, based in Poole) and high frequency speakers (eg Element6 est $14M market). These are all British companies that would benefit from the availability of large area single crystal CVD diamond material.

The UK is the leading producer of CVD diamond, Element6 (based in Ascot) being the largest diamond CVD operation worldwide. Element6 strongly support the development of new nucleation strategies and low temperature growth (see letter of support attached). Being able to grow single crystal diamond over large areas would drastically reduce the cost of diamond detectors and electronics. New applications can be envisioned where thin films of high quality single crystal diamond are required over large areas. For example, the eradication of the grain boundaries would mean that even very thin films of diamond would have the thermal conductivity of bulk diamond. This would make diamond the ultimate heat spreading material for active device regions in quantum cascade lasers, GaN HEMT structures, CMOS devices etc.

Thin film diamond or Nanocrystalline Diamond (NCD) is a relatively new form of diamond which is being commercially exploited by several startup companies including Advanced Diamond Technologies (ADT, USA), Diamond Materials GmbH (Germany) and sp3 Technologies (USA). The exploitation of NCD in many application areas is hampered by pin-holes, a defect this proposal aims to eradicate.