Wu Tian-Li, Tang Shun-Wei, Jiang Hong-Jia
International College of Semiconductor Technology, National Chiao Tung University, Hsinchu 30010, Taiwan.
Micromachines (Basel). 2020 Feb 3;11(2):163. doi: 10.3390/mi11020163.
In this work, recessed gate AlGaN/GaN metal-insulator-semiconductor high-electron-mobility transistors (MIS-HEMTs) with double AlGaN barrier designs are fabricated and investigated. Two different recessed depths are designed, leading to a 5 nm and a 3 nm remaining bottom AlGaN barrier under the gate region, and two different Al% (15% and 20%) in the bottom AlGaN barriers are designed. First of all, a double hump trans-conductance ()-gate voltage () characteristic is observed in a recessed gate AlGaN/GaN MIS-HEMT with a 5 nm remaining bottom AlGaN barrier under the gate region. Secondly, a physical model is proposed to explain this double channel characteristic by means of a formation of a top channel below the gate dielectric under a positive . Finally, the impacts of Al% content (15% and 20%) in the bottom AlGaN barrier and 5 nm/3 nm remaining bottom AlGaN barriers under the gate region are studied in detail, indicating that lowering Al% content in the bottom can increase the threshold voltage () toward an enhancement-mode characteristic.
在本工作中，制备并研究了具有双AlGaN势垒设计的凹槽栅AlGaN/GaN金属-绝缘体-半导体高电子迁移率晶体管（MIS-HEMT）。设计了两种不同的凹槽深度，使得栅极区域下方剩余5nm和3nm的底部AlGaN势垒，并设计了底部AlGaN势垒中两种不同的Al%（15%和20%）。首先，在栅极区域下方剩余5nm底部AlGaN势垒的凹槽栅AlGaN/GaN MIS-HEMT中观察到双峰跨导（ ）-栅极电压（ ）特性。其次，提出了一个物理模型，通过在正 下在栅极电介质下方形成顶部沟道来解释这种双通道特性。最后，详细研究了底部AlGaN势垒中Al%含量（15%和20%）以及栅极区域下方5nm/3nm剩余底部AlGaN势垒的影响，表明降低底部Al%含量可使阈值电压（ ）朝着增强型特性增加。
