Material, characterization and devices: The evolution of GaN as an electronic material

GaN-based materials are attractive as the basis for various types of power devices and for devices operated at high temperature. One of the major advantages of this material over other competitors (such as SIG) is that lattice-matched heterostructures( based on AlGaN or on InGaN) am available, allowing for the fabrication of new classes of RF power devices and LEDs. Highly resistive buffer layers can be grown which separate the active device regions from the semiconductor/substrate interface, improving FET performance. All of this is achieved while maintaining the high breakdown fields of the wide-bandgap semiconductors with good carrier mobility. In addition, other unique properties of the GaN system may be further exploited for novel devices. These include low (or negative) electron affinity and persistent photoconductivity. Of course, wide bandgap allows for the possibility of blue LEDs and lasers. The paper below reviews the evolving status of GaN material with respect to these properties and their device application.