By implanting a buffer made of argon, researchers have created GaN devices that can handle 10 times as much power. Credit: North Carolina State Univ.
Gallium nitride (GaN) material holds promise for emerging high-power devices
that are more energy efficient than existing technologies—but these GaN devices
traditionally break down when exposed to high voltages. Now researchers at
North Carolina State Univ. have solved the problem, introducing a buffer that
allows the GaN devices to handle 10 times greater power.
“For future renewable technologies, such as the smart grid or electric cars,
we need high-power semiconductor devices,” says Merve Ozbek, a Ph.D. student at
NC State and author of a paper describing the research. “And power-handling
capacity is important for the development of those devices.”
Previous research into developing high power GaN devices ran into obstacles,
because large electric fields were created at specific points on the devices’
edge when high voltages were applied—effectively destroying the devices. NC
State researchers have addressed the problem by implanting a buffer made of the
element argon at the edges of GaN devices. The buffer spreads out the electric
field, allowing the device to handle much higher voltages.
The researchers tested the new technique on Schottky diodes and found that
the argon implant allowed the GaN diodes to handle almost seven times higher
voltages. The diodes that did not have the argon implant broke down when exposed
to approximately 250 V. The diodes with the argon implant could handle up to
1,650 V before breaking down.
“By improving the breakdown voltage from 250 V to 1,650 V, we can reduce the
electrical resistance of these devices a hundredfold,” says Dr. Jay Baliga,
Distinguished Univ. Professor of Electrical and Computer Engineering at NC
State and co-author of the paper. “That reduction in resistance means that
these devices can handle ten times as much power.”
The paper, “Planar, Nearly Ideal Edge Termination Technique for GaN
Devices,” is forthcoming from IEEE’s Electron Device Letters. The
research was supported by NC State’s Future Renewable Electric Energy Delivery
and Management Systems Center,
with funding from the National Science Foundation.
NC State’s Department of Electrical and Computer Engineering is part of the