High-temperature performance of GaAs-based HFET structure containing LT-AlGaAs and LT-GaAs

Using low-temperature grown layers a GaAs-based HFET structure was developed, which demonstrates for the first time high performance at high temperatures up to 540 degrees C, where the gate diode shunts through, The device was designed for operation in the hot electron regime using an LT-AlGaAs passivation layer. Thug the open channel current density and gain bandwidth product are exceptionally stable (ID500 degrees C/I-DR.T. = 0.9; f(T200 degrees C)/f(TR.T.) = 0.9). The f(max) cutoff frequency is the most temperature sensitive parameter {(f(max)/f(T))(R.T.) = 3.9 and (f(max)/f(T))(200 degrees C) = 2.8} due to the thermal activation of the buffer layer leakage, which is kept extremely small using LT-GaAs.