Advanced substrates will enable future GaN-based devices
While most HB-LEDs are manufactured using sapphire or SiC substrates, emerging GaN-based device types will require more advanced materials.
In the future, increasing demand for blue-violet laser diodes, UV LEDs and high-power, high-frequency electronic devices will provide significant market opportunities for advanced substrates such as gallium nitride and aluminum nitride (AlN). These are predicted to comprise more than one-half of the market in 2010.
Until now, most GaN devices have been high-brightness LEDs manufactured using high-quality sapphire and silicon carbide substrates as the starting material in wafer sizes of 2-inch diameter and larger. The GaN device market exceeds $3 billion.
However, different device types require different substrates such as GaN and AlN that are able to provide the lattice matching and thermal characteristics necessary to produce high-performance devices at high yields. It is unlikely that manufactures of visible LEDs will switch to using these new substrates, at least until prices fall significantly.
AlN and GaN substrates are available but only in the form of small-diameter wafers. A number of companies are in a position to provide such substrates as the market expands. These include larger established companies such as Sumitomo Electric, Cree and Samsung Corning, as well as smaller technology-focused startups such as Crystal IS, The Fox Group, Kyma, Lumilog, TDI and TopGaN.
The effort to develop advanced substrates, as well as to improve conventional substrate properties (e.g. three-inch and larger diameter sapphire and silicon carbide), is worldwide in scope and includes 48 companies and 118 universities and research centers.