Large-signal characterization of THz emitter-fin InP/GaAsSb DHBTs with record G-band power added efficiency

Abstract Future telecommunication systems are set to revolutionize connectivity, driven by advancements in technologies like 6 G, artificial intelligence, and the Internet of Things (IoT). However, this evolution brings significant challenges. Traditional silicon-based transistors struggle to meet demands for efficiency and power handling. Indium Phosphide (InP)-based Double Heterojunction Bipolar Transistors (DHBTs) deliver excellent performance at sub-mm-wave frequencies while minimizing power loss and heat generation. Additionally, achieving reliable large-signal performance in high-frequency applications requires accurate large-signal modelling and advanced testing techniques, such as load-pull measurements. In this paper, we report the comparison between two InP/GaAsSb Double Heterojunction Bipolar Transistors (DHBTs) with different collector epitaxial designs in terms of their small- and large-signal performance. The effect of the epitaxial design on the small- and large-signal performances is investigated and load-pull measurements in G-band are performed to assess the great power-handling and efficiency capabilities of the InP/GaAsSb DHBT technology. For both of the designs, THz cut-off frequencies with Power-Added Efficiency (PAE) > 30% are achieved. Moreover, the value of PAE = 39.2% reached in G-band represents the highest among any technology. Finally, the two different epitaxial designs are thermally characterized to investigate the effect of different layers on the thermal and RF-performances.