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David J. Meyer

Bio: David J. Meyer is an academic researcher from United States Naval Research Laboratory. The author has contributed to research in topics: Molecular beam epitaxy & Epitaxy. The author has an hindex of 21, co-authored 126 publications receiving 1440 citations. Previous affiliations of David J. Meyer include United States Department of the Navy & Pennsylvania State University.


Papers
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Journal ArticleDOI
07 Mar 2018-Nature
TL;DR: The demonstration of the direct epitaxial growth of high-quality semiconductor heterostructures and devices on crystalline nitride superconductor opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic and piezoelectric properties of the group III/nitride semiconductor family.
Abstract: Epitaxy is a process by which a thin layer of one crystal is deposited in an ordered fashion onto a substrate crystal. The direct epitaxial growth of semiconductor heterostructures on top of crystalline superconductors has proved challenging. Here, however, we report the successful use of molecular beam epitaxy to grow and integrate niobium nitride (NbN)-based superconductors with the wide-bandgap family of semiconductors-silicon carbide, gallium nitride (GaN) and aluminium gallium nitride (AlGaN). We apply molecular beam epitaxy to grow an AlGaN/GaN quantum-well heterostructure directly on top of an ultrathin crystalline NbN superconductor. The resulting high-mobility, two-dimensional electron gas in the semiconductor exhibits quantum oscillations, and thus enables a semiconductor transistor-an electronic gain element-to be grown and fabricated directly on a crystalline superconductor. Using the epitaxial superconductor as the source load of the transistor, we observe in the transistor output characteristics a negative differential resistance-a feature often used in amplifiers and oscillators. Our demonstration of the direct epitaxial growth of high-quality semiconductor heterostructures and devices on crystalline nitride superconductors opens up the possibility of combining the macroscopic quantum effects of superconductors with the electronic, photonic and piezoelectric properties of the group III/nitride semiconductor family.

115 citations

Journal ArticleDOI
TL;DR: In this article, the authors demonstrate growth of ScxAl1-xN on GaN and SiC substrates using plasma-assisted molecular beam epitaxy with x'='0.14'-0.24'.
Abstract: ScxAl1-xN is a promising ultra-wide bandgap material with a variety of potential applications in electronic, optoelectronic, and acoustoelectric devices related to its large piezoelectric and spontaneous polarization coefficients. We demonstrate growth of ScxAl1-xN on GaN and SiC substrates using plasma-assisted molecular beam epitaxy with x = 0.14–0.24. For metal-rich growth conditions, mixed cubic and wurtzite phases formed, while excellent film quality was demonstrated under N-rich growth conditions at temperatures between 520 and 730 °C. An rms roughness as low as 0.7 nm and 0002 rocking curve full-width at half maximum as low as 265 arc sec were measured for a Sc0.16Al0.84 N film on GaN. To further demonstrate the quality of the ScAlN material, a high-electron-mobility transistor heterostructure with a Sc0.14Al0.86 N barrier, GaN/AlN interlayers, and a GaN buffer was grown on SiC, which showed the presence of a two-dimensional electron gas with a sheet charge density of 3.4 × 1013 cm−2 and a Hall mob...

81 citations

Journal ArticleDOI
TL;DR: In this article, a fully coupled multi-dimensional continuum model of the thermoelectromechanics of GaN HEMTs is presented and discussed, and the possibilities of crack propagation and fracture of the AlGaN are also analyzed.
Abstract: A fully coupled multi-dimensional continuum model of the thermoelectromechanics of GaN HEMTs is presented and discussed. The governing equations are those of linear thermoelectroelasticity, diffusion-drift transport theory, and heat conduction, with full coupling assumed, i.e., all mechanical, electrical, and thermal variables are solved for simultaneously. Apart from the known strains induced by epitaxy, plane-strain conditions are assumed, so that two-dimensional simulation suffices. Important aspects of the model are that it incorporates “actual” device geometries and that it captures field/stress concentrations that often occur near material discontinuities and especially at corners. The latter are shown to be especially important with regards to understanding the mechanisms of both electrical and mechanical degradation in GaN HEMTs. Various possible contributors to degradation are discussed, including electron injection, the inverse piezoelectric effect, thermal stress, SiN intrinsic stress, and device geometry. The possibilities of crack propagation and fracture of the AlGaN are also analyzed.

75 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of GaN surface pretreatments on the material and electrical properties of Al2O3 dielectric deposited by atomic layer deposition (ALD) were reported.
Abstract: We report the effects of GaN surface pretreatments on the material and electrical properties of Al2O3 dielectric deposited by atomic layer deposition (ALD). A layer of Al2O3 was deposited at different temperatures on metal organic chemical vapor deposition grown n-GaN that was treated with either H2O2:H2SO4 (1:5, piranha), HCl:H2O (1:1, HCl), or HF:H2O (1:1, HF) prior to Al2O3 deposition. The Al2O3 layers on piranha- and HF-treated GaN were observed to be uniformly smooth. The piranha pretreatment resulted in the lowest hysteresis. Pretreatment of the GaN surface with piranha removes carbon and hydroxylates the surface, resulting in better quality ALD Al2O3.

73 citations

Journal ArticleDOI
TL;DR: In this article, an epitaxial high-overtone bulk acoustic wave resonator (HBAR) was proposed to achieve a power injection efficiency of >99% from transducer to phonon cavity.
Abstract: Solid-state quantum acoustodynamic (QAD) systems provide a compact platform for quantum information storage and processing by coupling acoustic phonon sources with superconducting or spin qubits. The multi-mode composite high-overtone bulk acoustic wave resonator (HBAR) is a popular phonon source well suited for QAD. However, scattering from defects, grain boundaries, and interfacial/surface roughness in the composite transducer severely limits the phonon relaxation time in sputter-deposited devices. Here, we grow an epitaxial-HBAR, consisting of a metallic NbN bottom electrode and a piezoelectric GaN film on a SiC substrate. The acoustic impedance-matched epi-HBAR has a power injection efficiency >99% from transducer to phonon cavity. The smooth interfaces and low defect density reduce phonon losses, yielding (f × Q) and phonon lifetimes up to 1.36 × 1017 Hz and 500 µs respectively. The GaN/NbN/SiC epi-HBAR is an electrically actuated, multi-mode phonon source that can be directly interfaced with NbN-based superconducting qubits or SiC-based spin qubits. Acoustic resonators may find application for qubit coupling in compact quantum information and processing systems. Here the authors show a multi-phonon source with high quality factors and long phonon lifetimes via epitaxial high-overtone bulk acoustic resonators.

51 citations


Cited by
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Journal ArticleDOI
TL;DR: This collection of GaN technology developments is not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve.
Abstract: Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at the point where power conversion applications of GaN are at the cusp of commercialisation. The future for building on the work described here in ways driven by specific challenges emerging from entirely new markets and applications is very exciting. This collection of GaN technology developments is therefore not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve. First generation production devices are igniting large new markets and applications that can only be achieved using the advantages of higher speed, low specific resistivity and low saturation switching transistors. Major investments are being made by industrial companies in a wide variety of markets exploring the use of the technology in new circuit topologies, packaging solutions and system architectures that are required to achieve and optimise the system advantages offered by GaN transistors. It is this momentum that will drive priorities for the next stages of device research gathered here.

788 citations

Journal ArticleDOI
TL;DR: The UWBG semiconductor materials, such as high Al‐content AlGaN, diamond and Ga2O3, advanced in maturity to the point where realizing some of their tantalizing advantages is a relatively near‐term possibility.
Abstract: J. Y. Tsao,* S. Chowdhury, M. A. Hollis,* D. Jena, N. M. Johnson, K. A. Jones, R. J. Kaplar,* S. Rajan, C. G. Van de Walle, E. Bellotti, C. L. Chua, R. Collazo, M. E. Coltrin, J. A. Cooper, K. R. Evans, S. Graham, T. A. Grotjohn, E. R. Heller, M. Higashiwaki, M. S. Islam, P. W. Juodawlkis, M. A. Khan, A. D. Koehler, J. H. Leach, U. K. Mishra, R. J. Nemanich, R. C. N. Pilawa-Podgurski, J. B. Shealy, Z. Sitar, M. J. Tadjer, A. F. Witulski, M. Wraback, and J. A. Simmons

785 citations

Journal ArticleDOI
TL;DR: In this paper, high-voltage GaN field-effect transistors fabricated on Si substrates were reported to have high breakdown voltage of 1200 V and low dynamic on-resistance at highvoltage operation.
Abstract: This letter reports high-voltage GaN field-effect transistors fabricated on Si substrates. A halide-based plasma treatment was performed to enable normally off operation. Atomic layer deposition of Al2O3 gate insulator was adopted to reduce the gate leakage current. Incorporation of multiple field plates, with one field plate connected to the gate electrode and two field plates connected to the source electrode successfully enabled a high breakdown voltage of 1200 V and low dynamic on-resistance at high-voltage operation.

369 citations

Journal ArticleDOI
TL;DR: In this paper, the authors performed hybrid functional calculations of native point defects and dangling bonds (DBs) in α-Al2O3 to aid in the identification of charge-trap and fixed-charge centers in Al 2O3/III-V metaloxide-semiconductor structures.
Abstract: We performed hybrid functional calculations of native point defects and dangling bonds (DBs) in α-Al2O3 to aid in the identification of charge-trap and fixed-charge centers in Al2O3/III-V metal-oxide-semiconductor structures. We find that Al vacancies (VAl) are deep acceptors with transition levels less than 2.6 eV above the valence band, whereas Al interstitials (Ali) are deep donors with transition levels within ∼2 eV of the conduction band. Oxygen vacancies (VO) introduce donor levels near midgap and an acceptor level at ∼1 eV below the conduction band, while oxygen interstitials (Oi) are deep acceptors, with a transition level near the mid gap. Taking into account the band offset between α-Al2O3 and III-V semiconductors, our results indicate that VO and Al DBs act as charge traps (possibly causing carrier leakage), while VAl, Ali, Oi, and O DBs act as fixed-charge centers in α-Al2O3/III-V metal-oxide-semiconductor structures.

201 citations

Journal ArticleDOI
01 Mar 2015-Vacuum
TL;DR: Al 2 O 3 thin films were grown on highly-doped p-Si (100) macro-and mesoporous structures by atomic layer deposition (ALD) using trimethylaluminum (TMA) and water H 2 O as precursors at 300°C as discussed by the authors.

201 citations