Wide bandgap semiconductors

Opportunity for powder switching devices: wide bandgap semiconductors

Advances in power semiconductor technology have improved the efficiency, size, weight and cost of power electronic systems. At present, IGBTs, and MOSFETs represent modern switching devices. New components based on wide band gap materials (SiC and GaN) are on the way to be introduced for next generation of advanced applications.

(Left) Illustration of the superior material properties of
wide bandgap semiconductors (SiC, GaN) over silicon.1
(Right) On-resistance as a function of blocking voltage of various materials 2,3
Si-devices can not improve their properties due to its physical limitation. 
AlN is a candidate material for the next generation power devices. 

Wide Bandgap Semiconductors (WBG) such as SiC, GaN, AlN and diamond show superior material properties compared to Silicon, as displayed in the above figure. Due to these unique characteristics, these WBG represent the unique material of choice to help solving the energy problems of the future. The advanced features in benchmarking power devices include conduction modulation and superjunction in devices taking advantage of bipolar conduction. To this end, the GaN-AlN-InN material system (e.g. AlGaN, AlN, InGaN) has a unique advantage due to its prominent spontaneous and piezoelectric polarization effects and flexibility in inserting appropriate heterojunctions thus dramatically broadening the device design space. Systems employing GaN based devices have higher power efficiency, corresponding to lower losses, and higher switching frequencies, that allow to reduce the size and weight of the converters. Such properties allow for the implementation of electronics operating at high-switching speed, higher voltages, higher temperatures while maintaining high efficiencies. This unique performance provides a qualitative change in their application to energy processing.

A. Brown, PhD thesis 2015, Glasgow University
2 Wunderer et al., Phys. Status Solidi C, 9, 822, 2012
3 Okumura et al., Jpn. J. Appl. Phys., 45, 7565, 2006