Very low leakage InGaAs/InAlAs pHEMTs for broadband (300 MHz to 2 GHz) low-noise applications

This paper presents the design, fabrication and characterisation of InGaAs–InAlAs high electron mobility transistors (pHEMTs) suitable for low-frequency LNA designs. Very low levels of leakage, in the order of 0.05 A/cm2, are demonstrated by the pHEMTs, which have enabled the implementation of large-geometry, low-noise devices. Transistors with gate widths ranging from 200 μm to 1.2 mm are demonstrated to operate up to frequencies of 30 GHz. These are extremely promising as LNA components for implementation in broadband low-frequency systems as the very low-noise resistance simplifies matching requirements. The levels of leakage observed in our transistors further support the potential of the InGaAs/InAlAs material system as an alternative to Si when the CMOS roadmap comes to an end.