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High-current-density enhancement-mode AlGaN/GaN HEMT based on superlattice structure

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基于超晶格结构的高电流密度增强型 AlGaN/GaN HEMT

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Oct.2025, Vol.48 No.10: 1352-1356

DOI: 10.3969/j.issn.1003-5060.2025.10.008

Authors

XIA Yuanzhi, WU Chunyan, ZHOU Shigang, QIAN Junhan, YU Yongqiang

(School of Microelectronics, Hefei University of Technology, Hefei 230601, China)

Abstract and Keywords

Abstract: The recessed gate is a common technique for achieving enhancement-mode AlGaN/GaN high electron mobility transistor (HEMT). However, as the etching of the underlying AlGaN progresses, the polarization effect will be weakened, leading to a decrease in two-dimensional electron gas (2DEG) concentration and a significant reduction in current density. This paper proposes a recessed gate metal-insulator-semiconductor (MIS) structure with a superlattice (SL) layer under the gate. By introducing a 4 nm GaN/1 nm AlN SL layer between AlGaN and GaN, an additional layer of 2DEG channel is added to improve the electron density. Effects of recessed depth, gate medium and SL layer on device current density were simulated by using Silvaco TCAD software. The results reveal that for an AlGaN/GaN SL-MISHEMT featuring a 5 nm $ HfO_{2} $ gate dielectric layer and a SL layer (4 nm GaN/1 nm AlN), the threshold voltage $ V_{th} $ is 0.14 V, while the current density $ I_{ds} $ reaches 1 014 mA/mm ( $ V_{ds}=10~V, V_{gs}=10~V $). The threshold voltage is increased by 3.28 V when compared to a conventional AlGaN/GaN HEMT ( $ V_{th}=-3.16~V $), and the current density is increased by 24% when compared to AlGaN/GaN MISHEMT without SL layers.

Keywords: AlGaN/GaN high electron mobility transistor(HEMT); recessed gate; superlattice(SL);

作者信息

夏元治，吴春艳，周世刚，钱君涵，于永强

（合肥工业大学微电子学院，安徽合肥230601）

摘要和关键词

摘要: 凹槽栅是实现增强型 AlGaN/GaN 高电子迁移率晶体管(high electron mobility transistor, HEMT)的常见技术, 但随着栅下 AlGaN 的刻蚀, 极化效应减弱, 二维电子气(two-dimensional electron gas, 2DEG)浓度降低, 电流密度显著降低。文章提出在凹槽栅金属-绝缘层-半导体(metal-insulator-semiconductor, MIS)结构栅下叠加 4 nm GaN 和 1 nm AlN 超晶格(superlattice, SL)结构, 通过在 AlGaN 与 GaN 之间引入一层超晶格层、增加一层二维电子气沟道来提高电流密度, 并利用 Silvaco TCAD 软件系统仿真凹槽深度、栅介质以及超晶格层对器件电流密度的影响。仿真结果表明: 使用 5 nm HfO $ _{2} $ 栅介质层并增加一层超晶格层(4 nm GaN + 1 nm AlN)的 AlGaN/GaN SL-MISHEMT, 阈值电压 $ V_{th} $ 为 0.14 V, 电流密度 $ I_{ds} $ 达到 1014 mA/mm ( $ V_{ds} = 10 $ V, $ V_{gs} = 10 $ V); 与常规 AlGaN/GaN HEMT ( $ V_{th} = -3.16 $ V)相比, 器件阈值电压增加了 3.28 V; 与无超晶格层的 AlGaN/GaN MISHEMT 相比, 电流密度提高了 24%.

关键词: AlGaN/GaN 高 中图分类号：TN386.6

Funding

安徽省自然科学基金资助项目（2208085MF177）

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