A Comparative Study on the Degradation Behaviors of Ferroelectric Gate GaN HEMT with PZT and PZT/Al2O3 Gate Stacks

In this paper, the degradation behaviors of the ferroelectric gate Gallium nitride (GaN) high electron mobility transistor (HEMT) under positive gate bias stress are discussed. Devices with a gate dielectric that consists of pure Pb(Zr,Ti)O3 (PZT) and a composite PZT/Al2O3 bilayer are studied. Two d...

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Bibliographic Details
Published in:Micromachines (Basel) 2024-01, Vol.15 (1), p.101
Main Authors: Chen, Lixiang, Lu, Zhiqi, Fu, Chaowei, Bi, Ziqiang, Que, Miaoling, Sun, Jiawei, Sun, Yunfei
Format: Article
Language:English
Subjects:
Aluminum oxide
Bias
Bilayers
CAD
Chemical vapor deposition
Communication
Comparative studies
Computer aided design
Degradation
Dielectric strength
Electric fields
ferroelectric
Ferroelectric materials
Ferroelectricity
Gallium nitrides
GaN
High electron mobility transistors
Interlayers
Lead zirconate titanates
MIS (semiconductors)
MIS-HEMT
Organic chemicals
reliability
Semiconductor devices
Threshold voltage
Trapping
traps
Zirconium
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Summary:In this paper, the degradation behaviors of the ferroelectric gate Gallium nitride (GaN) high electron mobility transistor (HEMT) under positive gate bias stress are discussed. Devices with a gate dielectric that consists of pure Pb(Zr,Ti)O3 (PZT) and a composite PZT/Al2O3 bilayer are studied. Two different mechanisms, charge trapping and generation of traps, both contribute to the degradation. We have observed positive threshold voltage shift in both kinds of devices under positive gate bias stress. In the devices with a PZT gate oxide, we have found the degradation is owing to electron trapping in pre-existing oxide traps. However, the degradation is caused by electron trapping in pre-existing oxide traps and the generation of traps for the devices with a composite PZT/Al2O3 gate oxide. Owing to the large difference in dielectric constants between PZT and Al2O3, the strong electric field in the Al2O3 interlayer makes PZT/Al2O3 GaN HEMT easier to degrade. In addition, the ferroelectricity in PZT enhances the electric field in Al2O3 interlayer and leads to more severe degradation. According to this study, it is worth noting that the reliability problem of the ferroelectric gate GaN HEMT may be more severe than the conventional metal–insulator–semiconductor HEMT (MIS-HEMT).
ISSN:2072-666X
2072-666X
DOI:10.3390/mi15010101