Scientists at NASA's Glenn Research Center have received several patents for fabrication methods that speed the production of silicon carbide (SiC) sensors and electronics, reduce fabrication costs, and enable advanced semiconductor functionality at temperatures greater than 600 °C. Glenn has developed a method for fabricating ultra-thin SiC microstructures using a dopant selective reactive ion etching (DSRIE) technique that can create extremely thin diaphragms (approximately 2 microns), increasing sensor sensitivity and resolution. In addition, Glenn has developed a modular protective packaging that allows SiC-based electronic devices to survive and operate reliably at very high temperatures. These innovations improve the real-time monitoring of high-temperature harsh environments, such as jet and rocket engines, allowing faster response times and more accurate readings.
Devices with traditional electrical ohmic contacts cannot withstand high temperatures, and they experience significant performance degradation. As a result, devices with conventional ohmic contact metallization must be located in lower-temperature areas to avoid measurement errors.
To overcome this challenge, Glenn Research Center has developed a SiC fabrication method that allows sensors and electronics to withstand extreme temperatures. Conventional fabrication techniques require multiple time-consuming and costly processes to separately form ohmic contacts onto n- and p-type surfaces. Glenn's innovation creates universal and simultaneous ohmic contacts for both donor and acceptor (n- and p-type) SiC semiconductors. Its unique ohmic contact structure is stable at temperatures greater than 600 °C for short-duration applications. This breakthrough innovation greatly improves real-time monitoring of high-temperature or other harsh environments.
Glenn has also developed a precision method for fabricating ultra-thin SiC microstructures and diaphragms. Unlike conventional reactive ion etching (RIE), with which it is challenging to obtain SiC diaphragm thickness below 25 microns without punching through, Glenn's DSRIE technique allows for a structure thickness of approximately 2 microns. This allows ultra-thin SiC diaphragms to be fabricated in batches, thereby unlocking the broader capabilities of SiC micro-electromechanical systems (MEMS) and nano-electromechanical systems (NEMS).
In addition, Glenn has created a planar modular package that protects electronics and sensors in high-temperature environments. This packaging can benefit industries that need semiconductor-based sensors and electronics to function optimally in high-temperature, extreme vibration, and corrosive environments.
Potential applications include use in sensors in harsh environments, aerospace, automotive, communications, power generation, spacecraft, and oil and gas exploration.