Avogy: Vertical GaN Power Devices

Gallium nitride (GaN), a binary III-V bandgap material, has been used to make LEDs for the last several years. GaN has also been touted as the next big thing in power electronics and RF. To some degree, GaN has made inroads in RF, especially in high-end defense and aerospace applications.

But the technology is having mixed success in power electronics. Today’s GaN-on-silicon devices are lateral structures, meaning the current flows from the source to the drain on the surface.

The big problem? There is a lattice mismatch between GaN and silicon. In fact, lateral GaN-on-silicon devices could hit the wall at 600 volts, prompting the need for a next-generation technology, namely bulk vertical GaN transistors.

One startup, Avogy, is leading the charge in the development of bulk vertical GaN transistors. Avogy was founded in 2010, but the startup entered the limelight in 2014, when it raised $40 million in Series B funding. Intel Capital, a new investor, led the round. It also obtained funding from an existing investor, Khosla Ventures.

In 2013, Avogy also obtained $1.7 million in funding from the Advanced Research Projects Agency-Energy (ARPA-E), part of the U.S. Department of Energy. ARPA-E, which focuses on early-stage technologies, recently announced a program aimed at developing next-generation devices and materials for 1,200 volts and higher and 100 amp applications. The program is called SWITCHES, which is short for “Strategies for Wide-Bandgap, Inexpensive Transistors for Controlling High-Efficiency Systems.”

Avogy is one of several companies in the SWITCHES program. Based in San Jose, Calif., Avogy was founded by semiconductor veteran Isik Kizilyalli. Kizilyalli is the chief technology officer. Dinesh Ramanathan, a former executive at Cypress Semiconductor, is the president and CEO of Avogy. Pierre Lamond, a general partner at Khosla Ventures, is chairman.

In addition, Avogy has a fab in San Jose, which includes a 3,500-square-foot clean room. In the fab, it has lithography tools as well as multiple MOCVD reactors for use in growing GaN epitaxial layers. Most believe GaN-on-GaN is a challenging technology. “That’s one of the myths,” Kizilyalli said. “It’s expensive, but the prices are coming down and quality is improving over time.”

For some time, Avogy has been sampling its devices, mostly diodes, which have blocking voltages of 600-, 1,200-, and 1,700-volts. It has also been developing vertical JFETs.