US lab makes GaN CMOS FETs
HRL Laboratories, a US r&d lab owned by Boeing and General Motors, has announced what it believes is the first demonstration of GaN complementary metal-oxide-semiconductor (CMOS) FET technology. The findings were published January 6, 2016, in IEEE Electron Device Letters.
In doing so, it says it has established that the semiconductor's superior transistor performance can be harnessed in an integrated circuit. This breakthrough paves the way for GaN to become the technology of choice for power conversion circuits that are made in silicon today.
GaN transistors have excelled in both power switching and microwave/millimeter wave applications, but their potential for integrated power conversion has been unrealised. "Unless the fast-switching GaN power transistor is intentionally slowed down in power circuits, chip-to-chip parasitic inductance causes voltage instabilities," said Rongming Chu HRL senior staff research engineer and principal investigator.
Chu and his colleagues in HRL's Microelectronics Laboratory have overcome that limitation, developing a GaN CMOS technology that integrates enhancement-mode GaN NMOS and PMOS on the same wafer. "Integration of power switches and their driving circuitry on the same chip is the ultimate approach to minimising the parasitic inductance," Chu said.
Today, GaN transistors are being designed into radar systems, cellular base stations, and power converters like those found in computer notebook power adaptors. "In the near term, GaN CMOS IC applications could include power integrated circuits that manage electricity more efficiently while having a significantly smaller form factor and lower cost, and integrated circuits that can operate in harsh environments," he said. "In the long term, GaN CMOS has the potential to replace silicon CMOS in a wide range of products."
Chu concluded:"GaN CMOS IC was considered difficult or impossible, due to the challenge in making P-channel transistor and integrating an N-channel transistor. Our recent work opened up the possibility of making GaN CMOS ICs."
