Hong Sejun, Rana Abu ul Hassan Sarwar, Heo Jun-Woo, Kim Hyun-Seok
J Nanosci Nanotechnol. 2015 Oct;15(10):7467-71. doi: 10.1166/jnn.2015.11135.
Multiple techniques such as fluoride-based plasma treatment, a p-GaN or p-AlGaN gate contact, and a recessed gate structure have been employed to modulate the threshold voltage of AlGaN/GaN-based high-electron-mobility transistors (HEMTs). In this study, we present dual-gate AlGaN/GaN HEMTs grown on a Si substrate, which effectively shift the threshold voltage in the positive direction. Experimental data show that the threshold voltage is shifted from -4.2 V in a conventional single-gate HEMT to -2.8 V in dual-gate HEMTs. It is evident that a second gate helps improve the threshold voltage by reducing the two-dimensional electron gas density in the channel. Furthermore, the maximum drain current, maximum transconductance, and breakdown voltage values of a single-gate device are not significantly different from those of a dual-gate device. For the fabricated single- and dual-gate devices, the values of the maximum drain current are 430 mA/mm and 428 mA/mm, respectively, whereas the values of the maximum transconductance are 83 mS/mm and 75 mS/mm, respectively.
多种技术，如基于氟化物的等离子体处理、p型氮化镓或p型氮化铝镓栅极接触以及凹槽栅极结构，已被用于调节基于氮化铝镓/氮化镓的高电子迁移率晶体管（HEMT）的阈值电压。在本研究中，我们展示了生长在硅衬底上的双栅极氮化铝镓/氮化镓HEMT，其有效地将阈值电压正向移动。实验数据表明，阈值电压从传统单栅极HEMT中的-4.2 V移动到双栅极HEMT中的-2.8 V。显然，第二个栅极通过降低沟道中的二维电子气密度有助于提高阈值电压。此外，单栅极器件的最大漏极电流、最大跨导和击穿电压值与双栅极器件的这些值没有显著差异。对于制造的单栅极和双栅极器件，最大漏极电流值分别为430 mA/mm和428 mA/mm，而最大跨导值分别为83 mS/mm和75 mS/mm。
