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Home > News > Electrical transportation and piezotronic-effect modulation in AlGaN/GaN MOS HEMTs and unpassivated HEMTs

 

Highlights

 

The high-performance MOS HEMTs have been fabricated with 20 nm SiO2used as a gate-insulator.

The piezotronic effect is introduced to effectively modulate properties of HEMTs by applying external stress on the device.

The work provides deep comprehension and potential uses of the piezotronic-effect modulation AlGaN/GaN heterostructures.

Abstract

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.

Graphical abstract

We present empirical evidence that SiO2/AlGaN/GaN MOS HEMTs outperform the unpassivated AlGaN/GaN HEMTs with DC performances. The piezotronic effect is then introduced to modulate the drain current of HEMTs by applying external stresses on the devices effectively. 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.

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Keywords

AlGaN/GaN HEMT;2DEG;Piezotronic-effect;External stress

Source:ScienceDirect

 

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