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Title: Epitaxial Sc x Al 1− x N on GaN exhibits attractive high-K dielectric properties
Epitaxial Sc x Al 1− x N thin films of ∼100 nm thickness grown on metal polar GaN substrates are found to exhibit significantly enhanced relative dielectric permittivity (ε r ) values relative to AlN. ε r values of ∼17–21 for Sc mole fractions of 17%–25% ( x = 0.17–0.25) measured electrically by capacitance–voltage measurements indicate that Sc x Al 1− x N has the largest relative dielectric permittivity of any existing nitride material. Since epitaxial Sc x Al 1− x N 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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Applied Physics Letters
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National Science Foundation
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