27 March 2023
Ruggedness of CGD’s ICeGaN technology proven by Virginia Tech
Fabless semiconductor company Cambridge GaN Devices Ltd (CGD) — which was spun out of the University of Cambridge Department of Engineering’s Electrical Power and Energy Conversion group in 2016 by CEO Dr Giorgia Longobardi and professor Florin Udrea and designs, develops and commercializes power transistors and ICs that use GaN-on-silicon substrates — says that independent, third-party research by Virginia Tech University has demonstrated that its ICeGaN gallium nitride technology is more reliable and robust than other GaN platforms. Presented by researchers from Virginia Tech and CGD’s director of Innovation & Research Daniel Popa at the Applied Power Electronics Conference (APEC 2023) in Orlando, FL, USA (19–23 March), the paper ‘A GaN HEMT with Exceptional Gate Over-Voltage Robustness’ provides experimental evidence that shows that ICeGaN high-electron-mobility transistors (HEMTs), enabled by smart protection circuitry, show an exceptionally high over-voltage margin of over 70V (comparable to state-of-the-art traditional silicon devices) and possibly even higher.
“Accidental high drive voltage is a critical concern for the gate reliability and driver design of GaN HEMT devices,” says Popa. “State-of-the-art GaN HEMTs survive around 25V, which can be within gate voltage overshoots in applications such as converters, resulting in device failure,” he adds. “Until ICeGaN, higher breakdown voltage values of 70V and more were only possible with state-of-the-art SiC [silicon carbide] and superjunction devices.”
CGD claims that ICeGaN HEMTs possess a unique set of intrinsic capabilities that, together, elevate device reliability well above current state-of-the-art GaN devices from competitors, while approaching the ruggedness of state-of-the-art silicon-based devices. In addition to the hugely elevated dynamic gate breakdown capability, enabled by the inclusion of fully integrated GaN smart circuitry, and confirmed by the Virginia Tech research, ICeGaN technology has a higher voltage threshold of 3V, higher voltage range (0–20V), and a stronger gate voltage clamping action at lower temperatures.
Also, a novel Miller-clamp design, integrated within the smart ICeGaN circuitry, ensures immunity against high-dV/dt and high-dI/dt events and obviates the need for negative gate voltages for turning off (and keeping off) the HEMT, which in turn reduces exposure to dynamic Ron stress.
“The two major advantages of CGD’s ICeGaN technology are ease-of-use and reliability,” says chief commercial officer Andrea Bricconi. “Our design, which integrates smart protection circuitry fabricated in GaN on-chip with the HEMT, facilitates both these key benefits, enabling devices to be driven like a MOSFET — without the need for special gate drivers, complex and lossy driving circuits, negative voltage supply requirements or additional clamping components — and to survive rugged and challenging application conditions.”