Epitaxial ScxAl1−xN on GaN exhibits attractive high-K dielectric properties

Published In:
Applied Physics Letters
Volume: 120
Issue: 15
Publication Date: Apr 11, 2022
Authors: Joseph Casamento, Hyunjea Lee, Takuya Maeda, Ved Gund, Kazuki Nomoto, Len van Deurzen, Wesley Turner, Patrick Fay, Sai Mu, Chris G. Van de Walle, Amit Lal, Huili (Grace) Xing, Debdeep Jena

DOI: 10.1063/5.0075636


Epitaxial ScxAl1−xN thin films of ∼100 nm thickness grown on metal polar GaN substrates are found to exhibit significantly enhanced relative dielectric permittivity (εr) values relative to AlN. εr values of ∼17–21 for Sc mole fractions of 17%–25% (x = 0.17–0.25) measured electrically by capacitance–voltage measurements indicate that ScxAl1−xN has the largest relative dielectric permittivity of any existing nitride material. Since epitaxial ScxAl1−xN layers deposited on GaN also exhibit large polarization discontinuity, the heterojunction can exploit the in situ high-K dielectric property to extend transistor operation for power electronics and high-speed microwave applications.

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