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Threshold voltage mapping at the nanoscale of GaN-based high electron mobility transistor structures using hyperspectral scanning capacitance microscopy
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Saptarsi Ghosh ,
Peter De Wolf ,
Zhida Liang ,
Francesca Adams ,
Menno J. Kappers ,
David J. Wallis ,
Rachel A. Oliver
Applied Physics Letters, Volume: 124, Issue: 23
Swansea University Author:
Saptarsi Ghosh
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DOI (Published version): 10.1063/5.0203646
Abstract
Hyperspectral scanning capacitance microscopy (SCM) measures spectra at every XY location of a semiconductor sample surface area. We report its application to GaN-based high electron mobility transistor (HEMT) structures to map threshold voltage (Vth) at the nanoscale. The consistency between the co...
| Published in: | Applied Physics Letters |
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| ISSN: | 0003-6951 1077-3118 |
| Published: |
AIP Publishing
2024
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa66864 |
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| Abstract: |
Hyperspectral scanning capacitance microscopy (SCM) measures spectra at every XY location of a semiconductor sample surface area. We report its application to GaN-based high electron mobility transistor (HEMT) structures to map threshold voltage (Vth) at the nanoscale. The consistency between the conventional SCM data and the hyperspectral SCM data set of the same area on the HEMT surface provides evidence for the reliability of hyperspectral SCM. We developed a method to extract a map of Vth distribution across the surface of the HEMT structure at the nanoscale from the hyperspectral SCM data set. The map reveals that most of the fissures (i.e., enlarged pits formed at threading dislocation surface endings) on the nitride sample surface reduce local Vth. Other variations in Vth in regions free of the fissures could be a result of thickness and/or composition inhomogeneities in the barrier layer. Conventional SCM and other techniques cannot provide these detailed insights obtained through hyperspectral SCM. |
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| College: |
Faculty of Science and Engineering |
| Funders: |
C. Chen would like to thank the China Scholarship Council and the Cambridge Commonwealth, European & International Trust for a CSC Cambridge Scholarship. The authors would like to thank Dr. Gunnar Kusch for help in data analysis using HyperSpy. Materials studied here were grown using the EPSRC National Epitaxy Facility under EPSRC Grant No. EP/N017927/1. The measurements were performed using the Royce AFM Facility under Cambridge Royce facilities Grant No. EP/P024947/1 and Sir Henry Royce Institute recurrent Grant No. EP/R00661X/1. |
| Issue: |
23 |