Silicon Carbide Comes of Age, Offering Array of Advantages
Cree Research, Inc.

• Materials advances expected to boost power efficiency, optical storage capacity, and communications power.
• Spin-offs include two new companies and prospective markets for full-color displays and jewelry.
• Technology makes U.S. firm a leader in light-emitting diodes, next-generation semiconductors, and blue lasers.

Innovative processes for growing silicon carbide (SiC) crystals and making them into high-quality wafers are beginning to yield substantial economic benefits, including new U.S. companies and new international markets and prospects for substantial improvements in high-technology products ranging from electric vehicles to communications systems. SiC long has been known to have useful properties, including a tolerance for high temperatures, which makes it superior to conventional silicon crystals for certain electronics systems and, because of the high-energy wavelengths involved, blue light-emitting diodes (LEDs). The inherent potential of SiC was realized by Cree Research, Inc., which used co-funding from NIST's Advanced Technology Program (ATP) to develop new materials processing technologies that doubled wafer size from 1 to 2 inches and reduced the number of defects from 400 to 180 per cm2. These advances improved the yields and reduced the costs of LEDs and other devices made from SiC wafers and enabled the development of technologies that would otherwise not be commercially viable.

The ATP funding accelerated by 18 months the development of the basic substrate used in all products made by Cree, a small North Carolina company that reported $42.5 million in revenues in 1998, a 50 percent increase over the previous year. Among the more important results of the ATP project was a reduction in LED unit price from 46 cents to 18 cents. Low cost is a major inducement to customers such as Siemens A.G., which buys blue LEDs for applications such as the dashboard lighting in cars. The lightweight LEDs also offer advantages in "instant replay" boards for sports stadiums, a market that Cree has sought to capture by forming a wholly owned subsidiary, Real Color Displays, Inc., which sells modules that display full-motion video in more than 16 million colors. Other SiC applications being developed by Cree and its customers and research partners include power semiconductors, which could enhance by up to 20 percent the efficiency of electric vehicles and electric power switching systems; blue lasers, which could enable four- to eight-fold increases in the storage capacity of digital video disks; microwave devices that could increase the power and reduce the complexity of cellular base stations; powerful low-cost high- definition television systems; and diamond-like jewelry made of SiC crystals.

ATP funding: $1,957,000
Non-ATP funding: $435,000

April 1998