Ultrahigh-Speed GaN High-Electron-Mobility Transistors With fT/fmax of 454/444 GHz
Ultrahigh-Speed GaN High-Electron-Mobility Transistors With fT/fmax of 454/444 GHz
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DOI：
10.1109/led.2015.2421311
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发表时间：
2015-06-01
影响因子：
4.9
通讯作者：
Micovic, Miroslav
中科院分区：
文献类型：
--
作者：
Tang, Yan;Shinohara, Keisuke;Micovic, Miroslav
这封信报告了深度缩放的耗尽型GaN高电子迁移率晶体管（GaN-HEMT）的创纪录RF性能。基于AlN/GaN/AlGaN双异质结外延结构，采用自对准栅技术，通过分子束外延生长凹槽n（+）-GaN欧姆接触，制备了全钝化器件。在栅-源和栅-漏间距为50 nm的20 nm栅HEMT上实现了454 GHz的创纪录f（T）和444 GHz的同步f（max）。截止击穿电压为10 V时，该器件的约翰逊品质因数达到4.5 THz-V，代表了迄今为止GaN晶体管技术的最新性能。与以前的类似器件结构的E型GaN-HEMT相比，显著减小的非本征栅电容和提高的平均电子速度是改善频率特性的关键原因。
This letter reports record RF performance of deeply scaled depletion-mode GaN-high-electron-mobility transistors (GaN-HEMTs). Based on double heterojunction AlN/GaN/AlGaN epitaxial structure, fully passivated devices were fabricated by self-aligned-gate technology featuring recessed n(+)-GaN ohmic contact regrown by molecular beam epitaxy. Record-high f(T) of 454 GHz and simultaneous f(max) of 444 GHz were achieved on a 20-nm gate HEMT with 50-nm-wide gate-source and gate-drain separation. With an OFF-state breakdown voltage of 10 V, the Johnson figure of merit of this device reaches 4.5 THz-V, representing the state-of-the-art performance of GaN transistor technology to-date. Compared with previous E-mode GaN-HEMTs of similar device structure, significantly reduced extrinsic gate capacitance and enhanced average electron velocity are the key reasons for improved frequency characteristic.