Nitride-based high electron mobility transistors with a GaN spacer

A GaN/ultrathin AlN/GaN heterojunction has been used to introduce a GaN spacer between the GaN channel and the AlGaN barrier in AlGaN/GaN high electron mobility transistors (HEMTs). In conventional AlGaN/GaN devices, the alloy scattering of the electrons with the AlGaN barrier degrades the electron velocity at high electric fields. This effect is significantly reduced in GaN-spacer transistors, which therefore have much better high field transport properties. While the dc performance of these transistors is similar to conventional AlGaN/GaN HEMTs, a 20% increase in the electron velocity has been measured by two different techniques. (c) 2006 American Institute of Physics.