What is it about?

The report compares various gate leakage current mechanisms in AlGaN/GaN high electron mobility transistors. This simulation work shows that the primary path for electron transfer across the AlGaN barrier layer at medium and large negative gate voltages is through the one-dimensional energy states (traps) located at multiple energy levels within the AlGaN bandgap. The traps have been associated with threading dislocations. A simulation framework is developed to compute the current. The source of extensive leakage at very high temperatures has been identified.

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Why is it important?

GaN-based devices are routinely grown on foreign substrates and contain significant threading dislocations (TDs). The dislocation-related energy states degrade the optoelectronic properties of the devices. This simulation work effectively uncovers the role of TD-related states in leakage and reports on their electronic structure. The simulation framework developed in this report can be readily applied to analyze leakage in novel gate stacks.

Perspectives

Most reports analyzing gate leakage in GaN-based HEMTs give only a qualitative and incomplete picture of the electronic structure of the traps responsible for leakage. This report comprehensively compares various gate leakage mechanisms and extracts the density and energy levels of the traps contributing to leakage. The trap information derived in this work corroborates the findings of other experimental and theoretical reports. This report will help advance the field of defect identification through gate leakage current analysis.

Narendra Rai
Indian Institute of Technology Bombay

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This page is a summary of: Analysis and modeling of reverse-biased gate leakage current in AlGaN/GaN high electron mobility transistors, Journal of Applied Physics, December 2023, American Institute of Physics,
DOI: 10.1063/5.0176944.
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