InAlAs/InGaAs metamorphic HEMT with high current density and high breakdown voltage

An In0.3Al0.7As/In0.3Ga0.7As metamorphic power high electron mobility transistor (HEMT) grown on GaAs has been developed, This structure with 30% indium content presents several advantages over P-HEMT on GaAs and LM-HEMT on InP. A 0.15-mu m gate length device with a single delta doping exhibits a state-of-the-art current gain cut-off frequency F-t value of 125 GHz at V-ds = 1.5 V, an extrinsic transconductance of 650 mS/mm and a current density of 750 mA/mm associated to a high breakdown voltage of -13 V, Power measurements performed at 60 GHz demonstrate a maximum output power of 240 mW/mm with 6.4-dB power gain and a power added efficiency (PAE) of 25%. These are the first power results ever reported for any metamorphic HEMT.