Progress in High-Power, High Frequency AlGaN/GaN HEMTs

Fundamental concepts and processing of undoped, polarization-induced 2DEG AlGaN/GaN HEMTs are covered, along with device characterization. Special care is required to stabilize surface state charge with passivation. Frequency response and drain voltage breakdown are determined experimentally, and temperature rise is simulated. Gate width, loading, and the effect of channel differences in phase, in manifold HEMTs are considered for their impact on drain efficiency. Normalized power limits of 11–12 W/mm in single-channel devices and ∼6.5 W/mm in 1.5 mm devices are presented.