Liu Yang, Chen Changhao, Zhou Xiaowei, Li Peixian, Yang Bo, Zhang Yongfeng, Bai Junchun
School of Advanced Materials and Nanotechnology, Xidian University, Xi'an 710071, China.
State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, Xidian University, Xi'an 710071, China.
Micromachines (Basel). 2025 Jul 29;16(8):877. doi: 10.3390/mi16080877.
AlGaN-based high-electron-mobility transistors are critical for next-generation power electronics and radio-frequency applications, yet achieving stable enhancement-mode operation with a high threshold voltage remains a key challenge. In this work, we designed p-AlGaN superlattices with different structures and performed energy band structure simulations using the device simulation software Silvaco. The results demonstrate that thin barrier structures lead to reduced acceptor incorporation, thereby decreasing the number of ionized acceptors, while facilitating vertical hole transport. Superlattice samples with varying periodic thicknesses were grown via metal-organic chemical vapor deposition, and their crystalline quality and electrical properties were characterized. The findings reveal that although gradient-thickness barriers contribute to enhancing hole concentration, the presence of thick barrier layers restricts hole tunneling and induces stronger scattering, ultimately increasing resistivity. In addition, we simulated the structure of the enhancement-mode HEMT with p-AlGaN as the under-gate material. Analysis of its energy band structure and channel carrier concentration indicates that adopting p-AlGaN superlattices as the under-gate material facilitates achieving a higher threshold voltage in enhancement-mode HEMT devices, which is crucial for improving device reliability and reducing power loss in practical applications such as electric vehicles.
基于AlGaN的高电子迁移率晶体管对于下一代电力电子和射频应用至关重要，然而，实现具有高阈值电压的稳定增强模式操作仍然是一个关键挑战。在这项工作中，我们设计了具有不同结构的p-AlGaN超晶格，并使用器件模拟软件Silvaco进行了能带结构模拟。结果表明，薄势垒结构导致受主掺入减少，从而减少电离受主的数量，同时促进垂直空穴传输。通过金属有机化学气相沉积生长了具有不同周期厚度的超晶格样品，并对其晶体质量和电学性质进行了表征。研究结果表明，尽管梯度厚度势垒有助于提高空穴浓度，但厚势垒层的存在限制了空穴隧穿并引起更强的散射，最终增加了电阻率。此外，我们模拟了以p-AlGaN作为栅极下层材料的增强模式HEMT的结构。对其能带结构和沟道载流子浓度的分析表明，采用p-AlGaN超晶格作为栅极下层材料有助于在增强模式HEMT器件中实现更高的阈值电压，这对于提高器件可靠性和降低电动汽车等实际应用中的功率损耗至关重要。
