Impact of high-pressure annealing on characteristics of InGaAs/InAlAs metamorphic high-electron mobility transistors

High-pressure annealing (HPA) has emerged as a promising post-fabrication technique for enhancing carrier transport and reliability in semiconductor devices, yet its application to heterojunction-based III–V transistors remains limited. In this study, we explore the implementation of HPA in InGaAs/InAlAs metamorphic high-electron-mobility transistors to understand ambient-dependent effects in heterostructure interfaces. Representative annealing ambients, such as high-pressure nitrogen (HPNA) and deuterium (HPDA), were selected to assess the impact of ambient species on electrical performance. Through comprehensive characterization, including I–V and pulsed measurements and transmission-line method analysis, we systematically examined how HPA conditions influence trap behavior, channel resistance (Rch), and frequency response. HPNA can lead to reproducible improvements in DC performance, with a 6.20% increase in on-state current and a 5.76% enhancement in transconductance, alongside a 17.8% reduction in channel resistance, while maintaining a stable subthreshold swing. In contrast, HPDA-treated devices exhibited increased Rch and enhanced trap-related transient responses, offering insights into trap generation mechanisms in complex III–V interfaces. These results provide a valuable reference for the design of ambient-controlled annealing strategies and highlight the importance of tailoring HPA processes for the reliable integration of heterojunction-based transistors.