Role of stress voltage on structural degradation of GaN high-electron-mobility transistors

In GaN high-electron-mobility transistors, electrical degradation due to high-voltage stress is characterized by a critical voltage at which irreversible degradation starts to take place. Separately, cross-sectional TEM analysis has revealed significant crystallographic damage for severely degraded...

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Bibliographic Details
Published in:Microelectronics and reliability 2011-02, Vol.51 (2), p.201-206
Main Authors: Joh, Jungwoo, Alamo, Jesús A. del, Langworthy, Kurt, Xie, Sujing, Zheleva, Tsvetanka
Format: Article
Language:English
Subjects:
Applied sciences
Correlation
Degradation
Electric potential
Electronics
Exact sciences and technology
Gallium nitrides
Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
Stresses
Transistors
Transmission electron microscopy
Voltage
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Summary:In GaN high-electron-mobility transistors, electrical degradation due to high-voltage stress is characterized by a critical voltage at which irreversible degradation starts to take place. Separately, cross-sectional TEM analysis has revealed significant crystallographic damage for severely degraded devices. Furthermore, a close correlation between the degree of drain current degradation and material degradation has been reported. However, the role of the critical voltage in physical degradation has not been explored. In this work, we investigate the connection between electrical degradation that occurs around and beyond the critical voltage and the formation of crystallographic defects through detailed electrical and TEM analysis, respectively. We find that a groove in the GaN cap starts to be generated around the critical voltage. At higher voltages, a pit develops that penetrates into the AlGaN barrier. The size of the pit increases with stress voltage. We also observe a good correlation between electrical and material degradation.
ISSN:0026-2714
1872-941X
DOI:10.1016/j.microrel.2010.08.021