Theoretical study of electron mobility in AlGaN back-barrier Al2O3/InAlN/GaN heterostructures under optical phonon scattering

Considering the strong built-in electric field caused by polarization in wurtzite nitride heterostructures, the energy levels and wave functions of the two-dimensional electrons in AlyGa1−yN back-barrier Al2O3/InxAl1−xN/GaN heterostructures are calculated using the finite element difference method....

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Bibliographic Details
Published in:Journal of applied physics 2024-05, Vol.135 (17)
Main Authors: Liu, S., Xing, Y., Zhou, X. J.
Format: Article
Language:English
Subjects:
Aluminum gallium nitrides
Aluminum oxide
Barrier layers
Electric fields
Electron mobility
Electron states
Electrons
Energy levels
Finite element method
Gallium nitrides
Heterojunction devices
Heterostructures
Mathematical analysis
Matrix methods
Mixed crystals
Phonons
Scattering
Size effects
Transfer matrices
Wave functions
Wurtzite
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Summary:Considering the strong built-in electric field caused by polarization in wurtzite nitride heterostructures, the energy levels and wave functions of the two-dimensional electrons in AlyGa1−yN back-barrier Al2O3/InxAl1−xN/GaN heterostructures are calculated using the finite element difference method. The dispersion relations and electrostatic potentials of optical phonons are obtained by the transfer matrix method. The electron mobility under optical phonon scattering is studied based on the theory of Lei–Ting force balance equation. The influences of AlyGa1−yN back barrier, ternary mixed crystal effect, and size effect are also analyzed by comparing with the Al2O3/InxAl1−xN/GaN heterostructure without back barrier. It is found that the introduction of a back barrier can attenuate the effect of gate-insulating layer, but enhance the effect of barrier and channel layers on electronic states. Then, the interaction between electrons and optical phonons is weakened, so the electron mobility in AlyGa1−yN back-barrier Al2O3/InxAl1−xN/GaN heterostructure is higher than that in Al2O3/InxAl1−xN/GaN structure under the same conditions. It is also found that using a thinner AlyGa1−yN film with y = 0.25 as the back-barrier layer of Al2O3/InxAl1−xN/GaN heterostructure is more conducive to improving 2DEG mobility. These conclusions can provide references for the preparation of InxAl1−xN/GaN heterojunction devices.
ISSN:0021-8979
1089-7550
DOI:10.1063/5.0204253