Seo, Juwon Kim, Huiwon Lee, Won Jun Joo, Beom Soo Ko, Hyungduk Han, Il Ki Kang, Gumin Han, Jae-Hoon Ahn, DaeHwan Jeong, Mun Seok Kang, JoonHyun 2026-02-03T08:30:34Z 2026-02-03T08:30:34Z 2026-02-02 2026-01 0925-8388 https://pubs.kist.re.kr/handle/201004/154157 InP high electron mobility transistors (InP HEMTs) have attracted attention as cryogenic low noise amplifiers (LNAs) for quantum computing due to their high speed, high gain, and low-noise characteristics. Reducing gate leakage current is critical for achieving low-noise performance in InP HEMTs. Conventional approaches have mainly focused on optimizing the thickness of the lattice-matched In0.522Al0.478As layer to suppress the leakage current. However, leakage current still remains a major issue. Here, we propose a bandgap engineering approach using Al-rich In0.362Al0.638As layers to decrease the gate leakage current without increasing the layer thickness in InP HEMTs. The increased bandgap in Al-rich InAlAs decreases the gate leakage current and enhances electron confinement effect at the same thickness. In addition, the Al-rich InAlAs layer enables strain compensation for In-rich InGaAs channel layer and decrease the gate capacitance, which is favorable for high-speed operation. We successfully demonstrated low gate leakage InP HEMTs incorporating Al-rich In0.362Al0.638As in both the buffer and the spacer layers. Our InP HEMTs exhibited superior performance, achieving a high Ion/Ioff ratio of 1.5 × 105, a steep subthreshold swing (SS) of 65 mV/dec, and a high effective mobility of more than 9000 cm2/Vs, while maintaining a low gate leakage current of less than 6 nA/μm. This study will provide design guidelines for future low-noise InP HEMTs research. English Elsevier BV InP HEMTs employing strain-compensated Al-rich InAlAs for low-noise and low-power consumption Article 10.1016/j.jallcom.2026.185970 1 Journal of Alloys and Compounds, v.1051 Journal of Alloys and Compounds 1051 N scie scopus 001663410900001 2-s2.0-105026658187 Chemistry, Physical Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Chemistry Materials Science Metallurgy & Metallurgical Engineering Article TECHNOLOGY InP HEMT Al-rich InAlAs Strain compensation Gate leakage Effective mobility