Electrical transportation and piezotronic-effect modulation in AlGaN/GaN MOS HEMTs and unpassivated HEMTs
Electrical transportation and piezotronic-effect modulation in AlGaN/GaN MOS HEMTs and unpassivated HEMTs
复制标题
AlGaN/GaN MOS HEMT 和未钝化 HEMT 中的电传输和压电效应调制
DOI：
10.1016/j.nanoen.2017.06.041
复制
发表时间：
2017-09-01
期刊：
影响因子：
17.6
通讯作者：
Hu, Weiguo
中科院分区：
文献类型：
--
作者：
Liu, Ting;Jiang, Chunyan;Hu, Weiguo
金属氧化物半导体高电子迁移率晶体管（MOS HEMT）已被证明，并与传统的未钝化的AlGaN/GaN HEMT进行了比较。采用PECVD（等离子体增强化学气相沉积）方法沉积的20 nm SiO2层作为SiO2/AlGaN/GaN MOS HEMT的栅绝缘层。我们提出的经验证据表明，MOS HEMT优于传统的HEMT与直流性能。然后，压电效应被引入到调制的HEMT器件上施加外部应力的漏电流。在AlGaN/GaN界面的压电极化效应引起的面内张应变作用下，HEMT器件的饱和漏极电流减小。通过AlGaN/GaN异质结能带结构的能带分布研究了压电效应对二维电子气（2DEG）调制特性的作用机理和HEMT器件的电输运特性。引入三维应变模型，进一步模拟和说明了所提出的工作机制。该研究深入了解了压电子效应调制AlGaN/GaN异质结构中2DEG物理性质的工作原理，并为在HEMT和MEMS/NEMS器件中的潜在应用提供了指导。
The metal-oxide-semiconductor high-electron-mobility transistors (MOS HEMTs) have been demonstrated and compared with the conventional unpassivated AlGaN/GaN HEMTs. 20 nm SiO2 layer deposited by PECVD (plasma enhanced chemical vapor deposition) is used as a gate-insulator in the SiO2/AlGaN/GaN MOS HEMT. We present empirical evidence that MOS HEMTs outperforms the conventional HEMTs with DC performance. The piezotronic effect is then introduced to modulate the drain current of HEMTs by applying external stresses on the devices. The saturated drain currents of the HEMT devices decrease under in-plane tensile strain which is resulted from the piezoelectric polarization effect at the AlGaN/GaN interface. Working mechanism of the piezotronic effect modulating properties of 2DEG (two dimensional electron gases) and electrical transportation behavior of the HEMT devices are conducted via the band energy profile in the AlGaN/GaN heterstructure. 3D strain model is also induced to simulate and illustrate the proposed working mechanism further. This study provides in-depth comprehension into working principle of the piezotronic effect modulating physical properties of 2DEG in AlGaN/GaN hetero structures as well as guidance for the potential application in HEMT and MEMS/NEMS devices.