High power fast flexible electronics: Transparent RF AlGaN/GaN HEMTs on plastic substrates

Heat dissipation is a major challenge for practical applications of fast flexible electronics, particularly using wide band gap semiconductors, due to the high power needed to achieve high frequency operation. Using an intrinsic GaN buffer layer as a heat conductive conductor, transparent, flexible RF GaN HEMTs with a device area of 400 × 350 um² on plastic substrates (PET) are demonstrated with high thermal dissipation of 0.5 W. The device exhibits an f_MAX of 115 GHz with no severe degradation of device performance compared with that made on a Si substrate. Low temperature plastic substrates also exhibited no thermal damage/melting. Our approach demonstrated that flexible single crystal material such as intrinsic GaN is a contender for thermal management of medium power RF flexible devices.