NASA - National Aeronautics and Space Administration

NASA Technology Licensed for New MEMS Pressure Sensors

Glenn has licensed three patents, covering high-temperature, harsh-environment, silicon carbide (SiC) pressure sensors, to Endevco Corporation, San Juan Capistrano, Calif. Endevco is a leading designer and manufacturer of dynamic instrumentation for vibration shock and pressure measurements.

Pictured: Silicon carbide pressure sensor created using MEMS technology. Credit: Endevco Corp.

The NASA technologies licensed by Endevco include a packaging technique and chip fabrication methods developed by a team led by Dr. Robert Okojie for use in aircraft engine combustion chambers. SiC pressure sensors manufactured using these new processes can be used to improve testing of jet engines, in deep well drilling (where pressure and temperature rise as drilling depth increases), and in automobile combustion cylinders.

"The significant advantages of this innovation are very exciting," said Endevco President Scott Silcock. "We are in the process of transferring the NASA SiC process into our microelectromechnical systems (MEMS) manufacturing operation in Sunnyvale, with product availability for field testing in high-temperature applications targeted for later this year. We have also formed partnerships with companies that have an immediate need for this breakthrough technology."

Silicon carbide used for the new NASA technologies, rather than the traditional silicon, eliminates the need for cooling. The current generation of SiC-based pressure sensors has been demonstrated to operate for 130 hours at 600 degrees Celcius in air, making them durable and reliable for use for the first time in engine ground testing and short duration flight test instrumentation.

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According to Okojie, "Operation at high temperatures allows the SiC pressure sensors to be located in closer proximity to the sensed environment than conventional silicon-based sensors, which must be isolated or protected in a water-cooled, controlled environment. Placing the sensor closer to the environment provides more reliable measurements. Additionally, its lighter weight, due to absence of water-cooling plumbing, makes the device less complex, relatively inexpensive and reduces the down cycle for engine maintenance. Its light weight and reduced complexity also leads to less engine weight for flight vehicles, hence improved fuel efficiency."

In 2000 Glenn used an Endevco silicon-based accelerometer as the benchmark to validate the NASA Glenn SiC high-g accelerometer. Tests showed the NASA device operated as well as the Endevco benchmark device, but at higher temperatures. This initial result led to discussions between Endevco and Glenn about licensing opportunities to acquire Glenn's SiC pressure and accelerometer sensor fabrication and packaging technologies. Okojie will continue to work with Endevco to assist in overcoming any outstanding technical issues with the licensed technologies.

"The transfer of technology to industry is a significant part of NASA's heritage and charter," said Kathleen Needham, chief of Glenn's Technology Transfer and Partnerships Office. "We actively seek companies such as Endevco that have the ability and desire to bring NASA innovations to market."

Okojie's work is a combined effort of the Aviation Safety and Fundamental Aeronautics programs under NASA's Aeronautics Research Mission Directorate. For more information on Glenn's silicon carbide electronics work, visit http://www.grc.nasa.gov/WWW/SiC

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By Katherine Martin