Gallium Nitride (GaN) Device Technology Enhancements Leading to Advanced Transmit/Receive (T/R) Modules for Radar Performance Enhancement

We propose to increase the mobility of both n- and p-type GaN by applying tensile strain and fixing the strain by bonding to an appropriate heat sink material. Straining in other semiconductor materials is now recognized as a viable route to higherperformance. We have demonstrated in these systems how low-level strain (0.05%) can increase mobility by a factor of two. Increases were larger for p-type material than for n-type. In GaN systems p-type mobility is poor due to reduced material qualityarising from requisite large doping densities. Enhanced mobility would offset the need for such high doping and give an even greater benefit than that of the strain enhancement alone. The piezoelectric polarization within these systems indicates they wouldbe prime candidates for low-level-uniaxial strain enhancement. A conservative estimate of increased electronic performance using our technology is a factor of 4. This translates directly to circuit/system speed.This will be facilitated in part by the alleviation of the major weakness in GaN systems, i.e. that of poor quality p-type GaN. Our technology could facilitate p-type performance required for bipolar devices as well as complimentary circuits.