Power Electronics

The high electron density and mobility in the transistor channel of AlGaN/GaN HEMTs results in high breakdown voltages combined with low on-state resistances. The achievable high power density and low capacitive load are unmet by other semiconductor materials or transistor concepts and makes GaN transistors the first choice for developing novel highly efficient power switches in switching power supplies or AC motor-drive systems.

The power electronics group develops and investigates such power transistors and focuses on:

• Switching transistors for high voltages (up to 1000 V), low on-state resistance and high currents (up to 20 A)
• Normally-off transistors for voltages up to 1000 V

Process modules and the epitaxy design of the established FBH GaN technology get optimized to meet these goals.

Normally-off transistors in recess technology have been fabricated. The AlGaN barrier below the gate electrode, separating the gate from the transistor channel (2DEG) is reduced to as low as 4 nm. Breakdown voltages of more than 300 V have been realized with an optimized epitaxy design for the normally-off transistors.