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In this work, a step-graded (SG) AlGaN\/GaN HEMT is proposed and systematically investigated to explore the advantage of graded barrier compared to conventional HEMTs. The effect of Al-composition on DC\/RF performance of the conventional HEMT (CHEMT), is initially analyzed, where 25% Al composition delivered optimal performance. Further, a step-graded (SG) barrier (Al composition varying from 25% to 15%) is introduced, forming an SGHEMT. The outcomes show that, graded barrier allows for a modified 2DEG confinement resulting in more distributed carrier profile, offering improved and broader transconductance (g\n                    <jats:sub>m<\/jats:sub>\n                    ), and suppressed higher-order nonlinearities, thereby enhancing device linearity. Additionally, the impact of drain bias is also studied, where the SGHEMT achieves maximum performance at V\n                    <jats:sub>DS<\/jats:sub>\n                    = 5\u00a0V, due to enhanced electric field and improved carrier transport. Moreover, thickness of SG-AlGaN barrier is scaled from 22\u00a0nm to 11\u00a0nm to achieve better electrical performance. The optimized SGHEMT with 11\u00a0nm barrier is found to have g\n                    <jats:sub>m<\/jats:sub>\n                    of 420.4 mS\/mm, maximum I\n                    <jats:sub>D<\/jats:sub>\n                    of 1.83\u00a0A\/mm, higher I\n                    <jats:sub>d\u2212sat<\/jats:sub>\n                    of 2.82\u00a0A\/mm, &amp; enhanced f\n                    <jats:sub>T<\/jats:sub>\n                    of 154.3\u00a0GHz due to better channel electrostatics, enhanced carrier confinement, improved drive current capability. paving the way for better linearity performances. These results emphasize exceptional DC\/RF performance traits of proposed SGHEMT, rendering it a strong candidate for low-noise RF amplifiers that demand high linearity operation.\n                  <\/jats:p>","DOI":"10.1038\/s41598-026-61548-w","type":"journal-article","created":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T05:04:04Z","timestamp":1783573444000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":1,"title":["Step-graded AlGaN barrier engineering in AlGaN\/GaN HEMTs for high-linearity low-noise RF amplifiers"],"prefix":"10.1038","volume":"16","author":[{"given":"B.","family":"Mounika","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"J.","family":"Ajayan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ribu","family":"Mathew","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Srinivasa Rao","family":"Karumuri","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Asisa Kumar","family":"Panigrahy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,7,9]]},"reference":[{"issue":"1","key":"61548_CR1","doi-asserted-by":"publisher","first-page":"186","DOI":"10.1109\/TED.2024.3493062","volume":"72","author":"N Luo","year":"2025","unstructured":"Luo, N., Wen, H., Liu, W. & Jiang, L. 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