HIGH AL-CONTENT ALGAN GAN MODFETS FOR ULTRAHIGH PERFORMANCE/

The use of an AIGaN layer with high Al mole-fraction is proposed to in crease the equivalent figures of merit of the AIGaN/GaN MODFET structu re, It is shown that the room temperature mobility has little degradat ion with increasing Al mole-fraction up to 50%. 0.7-mu m gatelength Al 0.5Ga0.5N/GaN MODFET's by optical lithography exhibit a current densit y of 1 A/mm and three-terminal breakdown voltages up to 200 V, These d evices on sapphire substrates without thermal management also show CW power densities of 2.84 and 2.57 W/mm at 8 and 10 GHz, respectively, r epresenting a marked performance improvement for GaN-based FET's.