A team of Case Western Reserve University engineers has
designed and fabricated integrated amplifier circuits that operate under
extreme temperatures—up to 600 C—a feat that was previously impossible.
The silicon carbide amplifiers have applications in both
aerospace and energy industries. The devices can take the heat of collecting
data inside of nuclear reactors and rocket engines, for example.
Steven L. Garverick, PhD, a professor of electrical engineering
and computer science, describes the team’s work in a paper he presented at the
2012 IEEE EnergyTech conference. The paper is coauthored by PhD candidate
Chia-Wei Soong and Mehran Mehregany, director of the Case School of
Engineering, San Diego
program.
These integrated circuits are constructed on a wide-bandgap
semiconductor. According to Garverick, “Most semiconductors are made out
of silicon, but silicon will not function above 300 C, and there are some
important applications above that range.”
His team’s solution is to use silicon carbide. At high
temperatures, the material begins to act as a semiconductor.
Engineers at NASA Glenn Research
Center, in Cleveland, 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 altogether 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
can’t 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, 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 ten years away.
Source: Case Western Reserve University
