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Threshold voltage mapping at the nanoscale of GaN-based high electron mobility transistor structures using hyperspectral scanning capacitance microscopy

Chen Chen Orcid Logo, Saptarsi Ghosh Orcid Logo, Peter De Wolf Orcid Logo, Zhida Liang Orcid Logo, Francesca Adams Orcid Logo, Menno J. Kappers Orcid Logo, David J. Wallis Orcid Logo, Rachel A. Oliver Orcid Logo

Applied Physics Letters, Volume: 124, Issue: 23

Swansea University Author: Saptarsi Ghosh Orcid Logo

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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...

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Published in: Applied Physics Letters
ISSN: 0003-6951 1077-3118
Published: AIP Publishing 2024
Online Access: Check full text

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.
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