GaN for power devices: benefits, applications, and normally-off technologies

Gallium Nitride (GaN) based power devices have been demonstrated to deliver higher energy efficiency than their Silicon (Si) counterparts for 200-1.2kV rated applications. The benefits of GaN technologies and their market potential will be highlighted in this paper together with the main challenges that GaN-based power systems need to overcome to reach their full potential and finally enter the market. These challenges include: (i) normally-off operation, (ii) low threshold voltage (iii) high-voltage reliability, and (iv) unstable switching behaviour. A particular focus will be given to the solutions proposed in literature for obtaining the desired normally-off operation and enhanced stability. Finally, measurement results on one of the aspects related to the reliability of the gate of a commercially available normally-off GaN transistor will be discussed.