A team of Case Western Reserve University engineers has designed and fabricated integrated amplifier circuits that operate up to 600°C.
The silicon-carbide amplifiers have applications in aerospace and energy industries as they are claimed to be able to collect data inside nuclear reactors or rocket engines.
Dr Steven L Garverick, a professor of electrical engineering and computer science, described the team’s work in a paper he presented on 31 May at the 2012 IEEE EnergyTech conference, held at Case Western Reserve. The paper is co-authored by PhD candidate Chia-Wei Soong and Mehran Mehregany, director of the Case School of Engineering, San Diego programme.
These integrated circuits are constructed on a wide-band-gap semiconductor.
‘Most semiconductors are made out of silicon, but silicon will not function above 300°C, and there are some important applications above that range,’ said Garverick.
According to a statement, his team’s solution is to use silicon carbide because at high temperatures the material begins to act as a semiconductor.
Engineers at NASA Glenn Research Center pioneered techniques used to manufacture these circuits. Team members at Case Western Reserve have used them to fabricate complete circuits by depositing three distinct silicon-carbide layers on top of silicon-carbide wafers, which measure one-tenth of the thickness of a human hair.
These circuits are designed to replace the ‘dumb’ sensors currently used in high-temperature applications. The simple sensors cannot take the heat and instead require long wires that connect them to the high-temperature zone.
These circuits can experience considerable interference, which makes signals unclear and difficult to decipher. The physical enclosures and wiring used in the manufacture and installation of non-integrated sensors introduces additional error.
Integrating the amplifier and sensor into one discrete package and placing the package directly where data is being collected improves signal strength and clarity and produces more reliable information.
The researchers believe this will ultimately result in more accurate monitoring and safer control over a jet engine, nuclear reactor or other high-temperature operations.
The team has built a suite of circuits ranging from simple low-accuracy versions to more complex models that return far better data.
Garverick said the team will continue developing the technology and believes that commercial production is about five to 10 years away.