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Pingen K, Wolff N, Mohammadian Z, Sandström P, Beuer S, von Hauff E, Kienle L, Hultman L, Birch J, Hsiao CL, Hinz AM. III-Nitride Magnetron Sputter Epitaxy on Si: Controlling Morphology, Crystal Quality, and Polarity Using Al Seed Layers. ACS APPLIED MATERIALS & INTERFACES 2024; 16:34294-34302. [PMID: 38886009 PMCID: PMC11231972 DOI: 10.1021/acsami.4c03112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Revised: 05/06/2024] [Accepted: 05/10/2024] [Indexed: 06/20/2024]
Abstract
Group III-nitride semiconductors have been subject of intensive research, resulting in the maturing of the material system and adoption of III-nitrides in modern optoelectronics and power electronic devices. Defined film polarity is an important aspect of III-nitride epitaxy as the polarity affects the design of electronic devices. Magnetron sputtering is a novel approach for cost-effective epitaxy of III-nitrides nearing the technological maturity needed for device production; therefore, control of film polarity is an important technological milestone. In this study, we show the impact of Al seeding on the AlN/Si interface and resulting changes in crystal quality, film morphology, and polarity of GaN/AlN stacks grown by magnetron sputter epitaxy. X-ray diffraction measurements demonstrate the improvement of the crystal quality of the AlN and subsequently the GaN film by the Al seeding. Nanoscale structural and chemical investigations using scanning transmission electron microscopy reveal the inversion of the AlN film polarity. It is proposed that N-polar growth induced by Al seeding is related to the formation of a polycrystalline oxygen-rich AlN interlayer partially capped by an atomically thin Si-rich layer at the AlN/Si interface. Complementary aqueous KOH etch studies of GaN/AlN stacks demonstrate that purely metal-polar and N-polar layers can be grown on a macroscopic scale by controlling the amount of Al seeding.
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Affiliation(s)
- Katrin Pingen
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
| | - Niklas Wolff
- Synthesis
and Real Structure, Department of Material Science, Kiel University, Kaiserstrasse
2, D-24143 Kiel, Germany
- Kiel
Nano, Surface and Interface Science, Kiel
University, Christian-Albrechts-Platz
4, D-24118 Kiel, Germany
| | - Zahra Mohammadian
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Per Sandström
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Susanne Beuer
- Fraunhofer
Institute for Integrated Systems and Device Technology, Schottkystrasse 10, D-91058 Erlangen, Germany
| | - Elizabeth von Hauff
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
| | - Lorenz Kienle
- Synthesis
and Real Structure, Department of Material Science, Kiel University, Kaiserstrasse
2, D-24143 Kiel, Germany
- Kiel
Nano, Surface and Interface Science, Kiel
University, Christian-Albrechts-Platz
4, D-24118 Kiel, Germany
| | - Lars Hultman
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Jens Birch
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Ching-Lien Hsiao
- Department
of Physics, Chemistry and Biology, Linköpings
Universitet, SE-581 83 Linköping, Sweden
| | - Alexander M. Hinz
- Fraunhofer
Institute for Organic Electronics, Electron Beam and Plasma Technology, Winterbergstrasse 28, D-01277 Dresden, Germany
- Institute
of Solid State Electronics, Technische Universität
Dresden, Mommsenstrasse
15, D-01069 Dresden, Germany
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Pela RR, Hsiao CL, Hultman L, Birch J, Gueorguiev GK. Electronic and optical properties of core-shell InAlN nanorods: a comparative study via LDA, LDA-1/2, mBJ, HSE06, G0W0 and BSE methods. Phys Chem Chem Phys 2024; 26:7504-7514. [PMID: 38357814 DOI: 10.1039/d3cp05295h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Abstract
Currently, self-induced InAlN core-shell nanorods enjoy an advanced stage of accumulation of experimental data from their growth and characterization as well as a comprehensive understanding of their formation mechanism by the ab initio modeling based on Synthetic Growth Concept. However, their electronic and optical properties, on which most of their foreseen applications are expected to depend, have not been investigated comprehensively. GW and the Bethe-Salpeter equation (BSE) are regarded as the state-of-the-art ab initio methodologies to study these properties. However, one of the major drawbacks of these methods is the computational cost, much higher than density-functional theory (DFT). Therefore, in many applications, it is highly desirable to answer the question of how well approaches based on DFT, such as e.g. the local density approximation (LDA), LDA-1/2, the modified Becke-Johnson (mBJ) and the Heyd-Scuseria-Ernzerhof (HSE06) functionals, can be employed to calculate electronic and optical properties with reasonable accuracy. In the present paper, we address this question, investigating how effective the DFT-based methodologies LDA, LDA-1/2, mBJ and HSE06 can be used as approximate tools in studies of the electronic and optical properties of scaled down models of core-shell InAlN nanorods, thus, avoiding GW and BSE calculations.
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Affiliation(s)
- Ronaldo Rodrigues Pela
- Supercomputing Department, Zuse Institute Berlin (ZIB), Takustraße 7, 14195 Berlin, Germany.
| | - Ching-Lien Hsiao
- Thin film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE 581 83 Linköping, Sweden
| | - Lars Hultman
- Thin film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE 581 83 Linköping, Sweden
| | - Jens Birch
- Thin film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE 581 83 Linköping, Sweden
| | - Gueorgui Kostov Gueorguiev
- Thin film Physics Division, Department of Physics, Chemistry and Biology (IFM), Linköping University, SE 581 83 Linköping, Sweden
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Alves Machado Filho M, Hsiao CL, dos Santos RB, Hultman L, Birch J, Gueorguiev GK. Self-Induced Core-Shell InAlN Nanorods: Formation and Stability Unraveled by Ab Initio Simulations. ACS NANOSCIENCE AU 2023; 3:84-93. [PMID: 37101465 PMCID: PMC10125348 DOI: 10.1021/acsnanoscienceau.2c00041] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/14/2022] [Accepted: 10/14/2022] [Indexed: 04/28/2023]
Abstract
By addressing precursor prevalence and energetics using the DFT-based synthetic growth concept (SGC), the formation mechanism of self-induced InAlN core-shell nanorods (NRs) synthesized by reactive magnetron sputter epitaxy (MSE) is explored. The characteristics of In- and Al-containing precursor species are evaluated considering the thermal conditions at a typical NR growth temperature of around 700 °C. The cohesive and dissociation energies of In-containing precursors are consistently lower than those of their Al-containing counterparts, indicating that In-containing precursors are more weakly bonded and more prone to dissociation. Therefore, In-containing species are expected to exhibit lower abundance in the NR growth environment. At increased growth temperatures, the depletion of In-based precursors is even more pronounced. A distinctive imbalance in the incorporation of Al- and In-containing precursor species (namely, AlN/AlN+, AlN2/AlN2 +, Al2N2/Al2N2 +, and Al2/Al2 + vs InN/InN+, InN2/InN2 +, In2N2/In2N2 +, and In2/In2 +) is found at the growing edge of the NR side surfaces, which correlates well with the experimentally obtained core-shell structure as well as with the distinctive In-rich core and vice versa for the Al-rich shell. The performed modeling indicates that the formation of the core-shell structure is substantially driven by the precursors' abundance and their preferential bonding onto the growing edge of the nanoclusters/islands initiated by phase separation from the beginning of the NR growth. The cohesive energies and the band gaps of the NRs show decreasing trends with an increment in the In concentration of the NRs' core and with an increment in the overall thickness (diameter) of the NRs. These results reveal the energy and electronic reasons behind the limited growth (up to ∼25% of In atoms of all metal atoms, i.e., In x Al1-x N, x ∼ 0.25) in the NR core and may be qualitatively perceived as a limiting factor for the thickness of the grown NRs (typically <50 nm).
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Affiliation(s)
- Manoel Alves Machado Filho
- Thin
Film Physics Division, Department of Physics, Chemistry, and Biology
(IFM), Linköping University, SE 581 83Linköping, Sweden
- Universidade
Maurício de Nassau − UNINASSAU − Unidade Vitória
da Conquista, 45020-750Vitória da Conquista, Bahia, Brazil
| | - Ching-Lien Hsiao
- Thin
Film Physics Division, Department of Physics, Chemistry, and Biology
(IFM), Linköping University, SE 581 83Linköping, Sweden
| | | | - Lars Hultman
- Thin
Film Physics Division, Department of Physics, Chemistry, and Biology
(IFM), Linköping University, SE 581 83Linköping, Sweden
| | - Jens Birch
- Thin
Film Physics Division, Department of Physics, Chemistry, and Biology
(IFM), Linköping University, SE 581 83Linköping, Sweden
| | - Gueorgui K. Gueorguiev
- Thin
Film Physics Division, Department of Physics, Chemistry, and Biology
(IFM), Linköping University, SE 581 83Linköping, Sweden
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Deposition Mechanism and Properties of Plasma-Enhanced Atomic Layer Deposited Gallium Nitride Films with Different Substrate Temperatures. Molecules 2022; 27:molecules27238123. [PMID: 36500217 PMCID: PMC9740686 DOI: 10.3390/molecules27238123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/17/2022] [Accepted: 11/19/2022] [Indexed: 11/25/2022] Open
Abstract
Gallium nitride (GaN) is a wide bandgap semiconductor with remarkable chemical and thermal stability, making it a competitive candidate for a variety of optoelectronic applications. In this study, GaN films are grown using a plasma-enhanced atomic layer deposition (PEALD) with trimethylgallium (TMG) and NH3 plasma. The effect of substrate temperature on growth mechanism and properties of the PEALD GaN films is systematically studied. The experimental results show that the self-limiting surface chemical reactions occur in the substrate temperature range of 250-350 °C. The substrate temperature strongly affects the crystalline structure, which is nearly amorphous at below 250 °C, with (100) as the major phase at below 400 °C, and (002) dominated at higher temperatures. The X-ray photoelectron spectroscopy spectra reveals the unintentional oxygen incorporation into the films in the forms of Ga2O3 and Ga-OH. The amount of Ga-O component decreases, whereas the Ga-Ga component rapidly increases at 400 and 450 °C, due to the decomposition of TMG. The substrate temperature of 350 °C with the highest amount of Ga-N bonds is, therefore, considered the optimum substrate temperature. This study is helpful for improving the quality of PEALD GaN films.
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Zong T, Li L, Gao Q, Liu B, Yang X, Yang Y, Cui H. Passively Q-switched Tm:YAP laser with a tantalum aluminum carbide saturable absorber. APPLIED OPTICS 2022; 61:2432-2437. [PMID: 35333263 DOI: 10.1364/ao.451772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
Tantalum aluminum carbide (Ta4AlC3) phase ceramic (MAX) material has attracted much attention because of its high conductivity, high strength, corrosion resistance, and good optical properties. However, there are too few reports on lasers with Ta4AlC3-based saturable absorbers (SAs). We prepared and characterized a Ta4AlC3-based SA whose nonlinear absorption performances were achieved at a 2 µm waveband range and which was used in a passively Q-switched (PQS) Tm:YAP laser. In the PQS mode, a maximum average output power of 0.78 W was achieved with the central output wavelength of 1991.86 nm from a PQS Tm:YAP laser, corresponding to a pulse duration of 926 ns at 143.8 kHz.
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Kim DH, Schweitz MA, Koo SM. Effect of Gas Annealing on the Electrical Properties of Ni/AlN/SiC. MICROMACHINES 2021; 12:mi12030283. [PMID: 33800338 PMCID: PMC7998277 DOI: 10.3390/mi12030283] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 12/15/2022]
Abstract
It is shown in this work that annealing of Schottky barrier diodes (SBDs) in the form of Ni/AlN/SiC heterojunction devices in an atmosphere of nitrogen and oxygen leads to a significant improvement in the electrical properties of the structures. Compared to the non-annealed device, the on/off ratio of the annealed SBD devices increased by approximately 100 times. The ideality factor, derived from the current-voltage (IV) characterization, decreased by a factor of ~5.1 after annealing, whereas the barrier height increased from ~0.52 to 0.71 eV. The bonding structure of the AlN layer was characterized by X-ray photoelectron spectroscopy. Examination of the N 1 s and O 1 s peaks provided direct indication of the most prevalent chemical bonding states of the elements.
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Zaid H, Tanaka K, Liao M, Goorsky MS, Kodambaka S, Kindlund H. Self-Organized Growth of 111-Oriented (VNbTaMoW)N Nanorods on MgO(001). NANO LETTERS 2021; 21:577-582. [PMID: 33306398 DOI: 10.1021/acs.nanolett.0c04061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Refractory high-entropy alloy nitride, (VNbTaMoW)N, layers are grown on single-crystalline MgO(001) via ultrahigh vacuum direct current magnetron sputtering of a VNbTaMoW target in Kr/N2 gas mixtures at 1073 K. X-ray diffraction, scanning and transmission electron microscopy, and energy dispersive X-ray spectroscopy characterizations revealed the formation of B1-structured, 111-textured (V0.21Nb0.18Ta0.19Mo0.21W0.21)N1.05 with lattice parameter a = 0.4249 nm. The alloy nitride film exhibits dense columnar microstructure near the substrate-film interface with coherent 001 grain growth limited to a few tens of nanometers, followed by an outgrowth of quasi one-dimensional nanorods with 3-fold symmetric facets. We attribute the self-organized growth of rather unusual 111-textured nanorods on isostructural MgO(001) to kinetic limitations of the sputter-deposition process exacerbated by the sluggish diffusion of the multicomponent adspecies and the preferential growth of {111} crystals.
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Affiliation(s)
- Hicham Zaid
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
| | - Koichi Tanaka
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
| | - Michael Liao
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
| | - Mark S Goorsky
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
| | - Suneel Kodambaka
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
| | - Hanna Kindlund
- Department of Materials Science and Engineering, University of California Los Angeles, 410 Westwood Plaza, Los Angeles, California 90095 United States
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Kim DH, Min SJ, Oh JM, Koo SM. Fabrication and Characterization of Oxygenated AlN/4H-SiC Heterojunction Diodes. MATERIALS 2020; 13:ma13194335. [PMID: 33003505 PMCID: PMC7579660 DOI: 10.3390/ma13194335] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/23/2020] [Accepted: 09/24/2020] [Indexed: 11/16/2022]
Abstract
The effects of rapid thermal annealing (RTA) on Schottky barrier diodes (SBDs) made from oxygenated aluminum nitride (AlN) thin films deposited on a silicon carbide (SiC) substrate using radio frequency sputtering were investigated. The annealed SBD devices exhibited a 10x increase in the on/off current ratio vs. non-annealed devices for measurement temperatures ranging from 300 K to 450 K. The ideality factor, derived from the current density–voltage (J-V) characterization, increased by a factor of ~2.2 after annealing, whereas the barrier height decreased from ~0.91 to ~0.68 eV. Additionally, Auger electron spectroscopy indicated decreased concentrations of atomic oxygen in the AlN thin film, from ~36% before, to ~24% after annealing. This may have contributed to the reduced barrier height and improved on/off ratio in the annealed AlN/SiC diodes.
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Affiliation(s)
| | | | - Jong-Min Oh
- Correspondence: (J.-M.O.); (S.-M.K.); Tel.: +82-2-940-5763 (J.-M.O. & S.-M.K.)
| | - Sang-Mo Koo
- Correspondence: (J.-M.O.); (S.-M.K.); Tel.: +82-2-940-5763 (J.-M.O. & S.-M.K.)
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