Abstract: The material structure of GaAs-based InGaP/AlGaAs/InGaAs PHEMTs was optimized to obtain the positive threshold voltage of an enhancement-mode PHEMT.Contact-mode photolithography was used for realizing the monolithic integration of 0.8μm gate length GaAs-based InGaP/AlGaAs/InGaAs enhancement- and depletion-mode PHEMTs.Excellent DC and high frequency performance are achieved.VT,gm,JDSS,fT,and fmax are 0.1V,330mS/mm,245mA/mm,14.9GHz,and 18GHz for E-mode PHEMTs,and -0.5V,260mS/mm,255mA/mm,14.5GHz,and 20GHz for D-mode PHEMTs,respectively.DCFL inverters based on monolithic integration of GaAs-based InGaP/AlGaAs/InGaAs enhancement- and depletion-mode PHEMTs are fabricated.The supply voltage is 1V.When the input voltages are 0.15 and 0.3V,the output voltages are 0.98 and 0.18V, respectively.

Key words: monolithic integration, enhancement-mode, depletion-mode, PHEMT, threshold voltage