Evolution of structural defects associated with electrical degradation in AlGaN/GaN high electron mobility transistors
Name
del Alamo-Evolution of structural.pdf
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Author(s)
Makaram, Prashanth
Joh, Jungwoo
del Alamo, Jesus A.
Palacios, Tomas
Thompson, Carl V.
Date Issued
June 2010
Journal
Applied Physics Letters
Publisher
American Institute of Physics (AIP)
Citation
Makaram, Prashanth et al. “Evolution of Structural Defects Associated with Electrical Degradation in AlGaN/GaN High Electron Mobility Transistors.” Applied Physics Letters 96.23 (2010): 233509. © 2010 American Institute of Physics
Version
Final published version
Abstract
We have investigated the surface morphology of electrically stressed AlGaN/GaN high electron mobility transistors using atomic force microscopy and scanning electron microscopy after removing the gate metallization by chemical etching. Changes in surface morphology were correlated with degradation in electrical characteristics. Linear grooves formed along the gate edges in the GaN cap layer for all electrically stressed devices. Beyond a critical voltage that corresponds to a sharp increase in the gate leakage current, pits formed on the surface at the gate edges. The density and size of the pits increase with stress voltage and time and correlate with degradation in the drain current and current collapse. We believe that high mechanical stress in the AlGaN layer due to high-voltage stressing is relieved by the formation of these defects which act as paths for gate leakage current and result in electron trapping and degradation in the transport properties of the channel underneath.
MIT Department
MIT Materials Research Laboratory
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Materials Science and Engineering
Massachusetts Institute of Technology. Microsystems Technology Laboratories
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DOI of Published Version
https://doi.org/10.1063/1.3446869
