<p>Group III Nitride based field effect transistor (FETs) are provided having a power degradation of less than about 3.0 dB when operated at a drain-to-source voltage (V<SUB>DS</SUB>) of about 56 volts, a gate to source voltage (V<SUB>gs</SUB>) of from about -8 to about -14 volts and a temperature of about 140 °C for at least about 10 hours.</p>