Abstract: 200nm gate-length power InAlAs/InGaAs MHEMTs with T-shaped gate are characterized for DC,RF,and power performance.The MHEMTs show excellent DC output characteristics with an extrinsic transconductance of 510mS/mm and a threshold voltage of -1.8V.The fT and fmax obtained for the 0.2μm×100μm MHEMTs are 138 and 78GHz,respectively.Power characteristics are obtained under different frequencies.When input power (Pin) is -0.88dBm (or 2.11dBm), the MHEMTs exhibit high power characteristics at 8GHz.Output power (Pout) ,associated gain, power added efficiency (PAE) and density of Pout are 4.05(13.79)dBm,14.9(11.68)dB,67.74(75.1)%,254(239)mW/mm respectively.These promising results are on the path to the application of millimeter wave devices and integrated circuits with improved manufacturability over InP HEMT.

Key words: MHEMT, InAlAs/InGaAs, power characteristics, T-shaped gate