(In)AlGaN Heterojunction Field Effect Transistors and Circuits for High-Power Applications at Microwave and Millimeter-Wave Frequencies

Abstract

The suitability of the AlGaN/GaN heterostructure for applications up to 20 GHz is demonstrated based on a technically mature process. A broadband power amplifier integrated circuit is designed and fabricated in order to monitor the technology performance. Further, a 100 W power transistor for mobile communications is realized with an efficiency of 70% and an operation frequency of up to 3 GHz. We also demonstrate the performance of a 60 W switch-mode power amplifier module with 75% efficiency for industrial, scientific and medical applications at 2.4 GHz. To push the technology towards higher millimeter-wave frequencies an InAlGaN-based heterostructure was developed. This structure yields high sheet carrier concentration and mobility of 1.9×1013 cm-2 and 1590 cm2 V-1 s-1, respectively. An excellent fT of 110 GHz and fmax of 190 GHz were achieved with HFETs with a gate length of 100 nm. This allowed the realization of InAlGaN-based power amplifier monolithic microwave integrated circuits (MMICs) operating at millimeter-wave frequencies of 60 and 94 GHz.