60-GHz high power performance In0.35Al0.65As-In0.35Ga0.65As metamorphic HEMTs on GaAs

We report on a double-pulse doped, double recess In-0.35 Al-0.65 As-In-0.35 Ga-0.65 As metamorphic high electron mobility transistor (MHEMT) on GaAs substrate. This 0.15-mum gate MHEMT exhibits excellent dc characteristics, high current density of 750 mA/mm, extrinsic transconductance of 700 mS/mm. The on and off state breakdown are respectively of 5 and 13 V and defined at gate current density of 1 mA/mm. Power measurements at 60 GHz were performed on these devices. Biased between 2 and 5 V, they demonstrated a maximum output power of 390 mW/mm at 3.1 V of drain voltage with 2.8 dB power gain and a power added efficiency (PAE), of 18 %. The output power at 1 dB gain compression is still of 300 mW/mm. Moreover, the linear power gain is of 5.2 dB. This is to our knowledge the best output power density of any MHEMT reported at this frequency.