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

An In/sub 0.3/Al/sub 0.7/As/In/sub 0.3/Ga/sub 0.7/As 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-μm gate length device with a single /spl delta/ doping exhibits a state-of-the-art current gain cut-off frequency FTvalue of 125 GHz at V/sub 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.