Last year, NASA reported its first proof-of-concept
demonstration with an experimental SiC differential amplifier
that survived more than 1,700 hours at 932 degrees F--that's a
hundredfold increase in operational parameters over previous
silicon carbide prototypes. More recently, that same chip
surpassed 5,000 hours of operation at 932 degrees F. "Silicon
carbide is much harder and more expensive to process than
silicon," said Neudeck. "Our prolonged 500 degree C
demonstration chip was achieved through the successful
development and integration of a number of fundamental materials
and processing advancements here at NASA." One key obstacle, he
said, was development of the metal-semiconductor contacts needed
to carry electrical signals in and out of SiC transistors. NASA
colleague Robert Okojie overcame that problem with contacts that
have survived "thousands of hours of testing at 500 degrees C,"
Neudeck said. In addition, he said, the team overcame other
challenges "in high-temperature packaging, insulators