Strongly dispersive dielectric properties of high-ScN-fraction ScAlN deposited by molecular beam epitaxy

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Main Authors: Gokhale, Vikrant J., Champlain, James G., Hardy, Matthew T., Hart, James L., Lang, Andrew C., Mukhopadhyay, Saikat, Roussos, Jason A., Mack, Shawn C., Giribaldi, Gabriel, Colombo, Luca, Rinaldi, Matteo, Downey, Brian P.
Format: Preprint
Published: 2025
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author Gokhale, Vikrant J.
Champlain, James G.
Hardy, Matthew T.
Hart, James L.
Lang, Andrew C.
Mukhopadhyay, Saikat
Roussos, Jason A.
Mack, Shawn C.
Giribaldi, Gabriel
Colombo, Luca
Rinaldi, Matteo
Downey, Brian P.
author_facet Gokhale, Vikrant J.
Champlain, James G.
Hardy, Matthew T.
Hart, James L.
Lang, Andrew C.
Mukhopadhyay, Saikat
Roussos, Jason A.
Mack, Shawn C.
Giribaldi, Gabriel
Colombo, Luca
Rinaldi, Matteo
Downey, Brian P.
contents We present a comprehensive study of dielectric properties including complex permittivity, loss, and leakage of high-ScN-fraction ScAlN thin films grown using molecular beam epitaxy (MBE). Dielectric spectroscopy is carried out on high-ScN-fraction (30%-40% ScN fraction) samples from 20 Hz to 10 GHz. We find that real permittivity ε' increases significantly with increasing ScN fraction; a trend confirmed by density functional theory. Further, ε' is strongly dispersive with frequency and increasing ScN fraction, with values for Sc0.4Al0.6N varying from 150 down to 60 with increasing frequency. Loss, dispersion, and DC leakage current correspondingly increase with ScN fraction. The high ε' and strongly dispersive behavior in MBE ScAlN are not observed in a sputter-deposited ScAlN control with a similar ScN fraction, highlighting fundamental differences between films produced by the two deposition methods. Microscopy and spectroscopy analyses are carried out on MBE- and sputter-deposited samples to compare microstructure, alloy, and dopant concentration.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04539
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Strongly dispersive dielectric properties of high-ScN-fraction ScAlN deposited by molecular beam epitaxy
Gokhale, Vikrant J.
Champlain, James G.
Hardy, Matthew T.
Hart, James L.
Lang, Andrew C.
Mukhopadhyay, Saikat
Roussos, Jason A.
Mack, Shawn C.
Giribaldi, Gabriel
Colombo, Luca
Rinaldi, Matteo
Downey, Brian P.
Materials Science
Mesoscale and Nanoscale Physics
We present a comprehensive study of dielectric properties including complex permittivity, loss, and leakage of high-ScN-fraction ScAlN thin films grown using molecular beam epitaxy (MBE). Dielectric spectroscopy is carried out on high-ScN-fraction (30%-40% ScN fraction) samples from 20 Hz to 10 GHz. We find that real permittivity ε' increases significantly with increasing ScN fraction; a trend confirmed by density functional theory. Further, ε' is strongly dispersive with frequency and increasing ScN fraction, with values for Sc0.4Al0.6N varying from 150 down to 60 with increasing frequency. Loss, dispersion, and DC leakage current correspondingly increase with ScN fraction. The high ε' and strongly dispersive behavior in MBE ScAlN are not observed in a sputter-deposited ScAlN control with a similar ScN fraction, highlighting fundamental differences between films produced by the two deposition methods. Microscopy and spectroscopy analyses are carried out on MBE- and sputter-deposited samples to compare microstructure, alloy, and dopant concentration.
title Strongly dispersive dielectric properties of high-ScN-fraction ScAlN deposited by molecular beam epitaxy
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2502.04539