Qiuen Li, Xuanwu Kang, Hao Wu, Rikang Zhao, Yingkui Zheng, Hengyu Shang, Xinyu Liu and Chengjun Huang
{"title":"Capacitance reduction in AlGaN/GaN heterojunction diodes through thermally oxidized NiO anode","authors":"Qiuen Li, Xuanwu Kang, Hao Wu, Rikang Zhao, Yingkui Zheng, Hengyu Shang, Xinyu Liu and Chengjun Huang","doi":"10.35848/1347-4065/ad6ed5","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6ed5","url":null,"abstract":"In this study, a thin barrier AlGaN/GaN heterojunction diode with a NiO anode is proposed. NiO as an anode combined with a 5 nm AlGaN barrier layer can significantly deplete two-dimensional electron gas in the anode region of the device. Combined with the etching-free technology, the damage caused by etching the AlGaN barrier layer is successfully avoided. The capacitance of the device was reduced from 28 pF mm−1 (Schottky) to 966 fF/mm (NiO) which reduced 97%. At the same time the NiO anode devices with a reverse current leakage of ~10−8 A/mm@−100V achieved a high current ON/OFF ratio of ~10-8. NiO not only reduces the capacitance and leakage of the device but also enhances its anti-collapse ability. Without using the structure of field plates, the breakdown voltage of the device was also increased compared with the Schottky diode.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"7 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142227051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Masahiro Kaneko, Hiroki Miyake and Hiroyuki Nishinaka
{"title":"Demonstration of β-(Al x Ga1−x )2O3/β-Ga2O3 superlattice growth by mist chemical vapor deposition","authors":"Masahiro Kaneko, Hiroki Miyake and Hiroyuki Nishinaka","doi":"10.35848/1347-4065/ad6f87","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6f87","url":null,"abstract":"This study demonstrates the successful growth of a β-(AlxGa1−x)2O3/β-Ga2O3 superlattice structure with six periods using mist CVD. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis revealed that the superlattice consisted of six periods of β-(AlxGa1−x)2O3/β-Ga2O3 with an individual layer thickness of 12.9 nm and 9.1 nm, respectively. XRD analysis further confirmed the periodicity of the structure, yielding a period of 22.7 nm, which is in good agreement with the STEM result. Additionally, the Al composition was determined to be x = 0.085 based on XRD peak positions. Both atomic force microscopy and HAADF-STEM observations revealed atomically flat surfaces and sharp interfaces. This achievement highlights the potential of mist CVD for fabricating complex oxide heterostructures, offering a cost-effective and scalable alternative to conventional methods. The findings open new avenues for developing advanced electronic and optoelectronic devices based on wide-bandgap oxides.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"7 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A preliminary investigation into the potential of Ge-enhanced Cu2SnS3 (CTS) thin-film applications for water-splitting photoelectrodes","authors":"Daiki Kanamori and Mutsumi Sugiyama","doi":"10.35848/1347-4065/ad7433","DOIUrl":"https://doi.org/10.35848/1347-4065/ad7433","url":null,"abstract":"This study explores the potential of Ge-enhanced Cu2SnS3 (CTS) thin-films as photoelectrode materials for water splitting grown through a simple sulfurization process. The addition of Ge to CTS enabled tuning the bandgap and improved the photocurrent density. Films sulfurized at 520 °C exhibit enhanced grain size and reduced grain boundaries, which contribute to increased carrier transport efficiency. By optimizing Ge content and sulfurization conditions, the Cu2(Sn1−x,Gex)S3 films demonstrate promising capabilities for efficient green hydrogen production. This work lays the groundwork for developing advanced photoelectrodes and highlights the need for further refinement to maximize performance for practical applications.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"13 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hideaki Tanimura, Yuma Ueno, Tomoya Mifune, Hironori Fujisawa, Seiji Nakashima, Ai I. Osaka, Shinichi Kato and Takumi Mikawa
{"title":"Low-thermal-budget crystallization of ferroelectric Al:HfO2 films by millisecond flash lamp annealing","authors":"Hideaki Tanimura, Yuma Ueno, Tomoya Mifune, Hironori Fujisawa, Seiji Nakashima, Ai I. Osaka, Shinichi Kato and Takumi Mikawa","doi":"10.35848/1347-4065/ad70bf","DOIUrl":"https://doi.org/10.35848/1347-4065/ad70bf","url":null,"abstract":"We report the use of a low-thermal-budget annealing technique; flash lamp annealing (FLA), which provides an extremely short annealing time in the millisecond range, on the ferroelectric properties of Al-doped HfO2 (HAO) films. HAO annealed at 1000 °C with 5 ms shows a higher remanent polarization value of 24.9 μC cm−2 compared to rapid thermal annealing (RTA), without degradation of endurance. GIXRD shows a stronger peak intensity originating from the orthorhombic (o-) phase and is observed when using FLA, indicating the formation of a larger amount of the o-phase. We believe that this is a consequence of the low thermal budget of FLA, and that specifically FLA can minimize the relaxation of the compressive stress in the TiN electrodes, inducing a high tensile stress to the HAO films and therefore an enhancement of o-phase formation. These results indicate that FLA is a promising annealing method for HAO crystallization due to the enhancement of o-phase formation.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"65 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spin-wave emission using a V-shaped antenna","authors":"Ryota Yoshida, Shoki Nezu and Koji Sekiguchi","doi":"10.35848/1347-4065/ad71d8","DOIUrl":"https://doi.org/10.35848/1347-4065/ad71d8","url":null,"abstract":"We investigated the dynamics of spin waves in micro-patterned Permalloy thin films using time-resolved magneto-optic Kerr effect microscopy (TR-MOKE). By applying an external magnetic field, we observe the field dependence of spin wave signals with picosecond resolution. Fourier transform analysis of the signals confirms their agreement with the dispersion relation, demonstrating the successful detection of propagating spin waves using the MOKE technique. Furthermore, we perform dynamic measurements of interfering spin waves generated by a V-shaped antenna. The experimental results reveal differences in spin wave amplitude at each detection point. In combination with simulation analysis based on wave propagation from the V-shaped antenna, we reproduced the experimental results and revealed the existence of a protective zone.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"55 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218098","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Alexander Martin, Naho Kato, Tobias Fey, Kyle G. Webber, Ken-ichi Kakimoto
{"title":"Increased thermal stability by the addition of ZrO2 into a 0.48Ba(Zr0.2Ti0.8)O3-0.52(Ba0.7Ca0.3)TiO3 matrix material","authors":"Alexander Martin, Naho Kato, Tobias Fey, Kyle G. Webber, Ken-ichi Kakimoto","doi":"10.35848/1347-4065/ad6c58","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6c58","url":null,"abstract":"Ferroelectric ceramics based on <italic toggle=\"yes\">x</italic>(Ba<sub>0.7</sub>Ca<sub>0.3</sub>)TiO<sub>3</sub>–(1−<italic toggle=\"yes\">x</italic>)Ba(Zr<sub>0.2</sub>Ti<sub>0.8</sub>)O<sub>3</sub> (BCZT100x) are regarded as promising lead-free candidates for piezoelectric applications. Heightened piezoelectric properties are found around specific temperatures, i.e. polymorphic phase boundaries. As broader thermal stability is required for certain applications, this study aims to increase the diffusiveness of the phase transitions by introducing ZrO<sub>2</sub> as a filler material into a BCZT52 matrix. The diffuseness factor of the Curie point was evaluated and increased from approximately 1.60 to 1.88 with the addition of 4 vol% ZrO<sub>2</sub> to BCZT52. As a result, samples with an additional 2 vol% showed the highest thermal stability in the temperature range between 25 °C and 70 °C. Here, the large signal piezoelectric strain coefficient <inline-formula>\u0000<tex-math>\u0000<?CDATA ${d}_{33}^{* }$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msubsup><mml:mrow><mml:mi>d</mml:mi></mml:mrow><mml:mrow><mml:mn>33</mml:mn></mml:mrow><mml:mrow><mml:mo>*</mml:mo></mml:mrow></mml:msubsup></mml:math>\u0000<inline-graphic xlink:href=\"jjapad6c58ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> degraded only by 18%, compared to 30% in BCZT52. This increase was caused by the inhomogeneous distribution of Zr within the sample.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"4 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Synchrotron radiation Fourier-transform infrared absorption measurements on the single-crystal dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene","authors":"Yasuo Nakayama, Kaname Yamauchi, Yuya Baba, Kazuhide Kikuchi, Hiroyuki Hattori, Fumitsuna Teshima, Kiyohisa Tanaka","doi":"10.35848/1347-4065/ad70c0","DOIUrl":"https://doi.org/10.35848/1347-4065/ad70c0","url":null,"abstract":"The strong coupling of charge carriers with molecular vibrations is one essential characteristic of organic semiconductor materials as molecular solids. To address this question, fundamental solid-state properties of each molecular species are demanded not only for the electronic states but also for the vibrational characteristics. In the present study, Fourier-transform infrared absorption measurements were performed on single-crystal samples of dinaphtho[2,3-<italic toggle=\"yes\">b</italic>:2′,3′-<italic toggle=\"yes\">f</italic>]thieno[3,2-<italic toggle=\"yes\">b</italic>]thiophene (DNTT) by using a linearly polarized synchrotron radiation light source. Molecular vibrational modes in a wavenumber range of 200–1600 cm<sup>−1</sup> were reasonably assigned, and the Davydov splittings of several vibrational modes were resolved demonstrating intermolecular couplings of two DNTT molecules in the unit cell.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"11 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Study of selective etching of TaN with respect to SiOCH dielectrics using SiF4 plasma processes","authors":"Ivo Otto IV, Christophe Valleé","doi":"10.35848/1347-4065/ad6f85","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6f85","url":null,"abstract":"TaN is used as a Cu diffusion barrier during metal interconnect formation to enable modern chip fabrication. In this study, the selective removal of TaN with respect to SiOCH dielectrics is explored using neutral dominant plasmas containing pure SiF<sub>4</sub> or with O<sub>2</sub> or H<sub>2</sub> additives. SiF<sub>4</sub> is studied because the Si-containing gas has been historically used to deposit Si-based films, but the gas also contains F capable of volatilizing Ta. This work explores the possibility of enabling both selective etching of TaN and selective deposition on SiOCH. SiF<sub>4</sub> discharges are impacted by the addition of O<sub>2</sub> and H<sub>2</sub> gases; exhibiting significantly different deposition and etching regimes. The substrate temperature plays a critical role in modulating the TaN etching versus deposition window compared to SiOCH. Through this work, selective etching of TaN with respect to SiOCH is achieved.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"61 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Synthesis of ternary titanium–niobium nitride nanoparticles by induction thermal plasma","authors":"Yirong Wang, Kaiwen Zhang, Motonori Hirose, Junya Matsuno, Manabu Tanaka, Takayuki Watanabe","doi":"10.35848/1347-4065/ad70be","DOIUrl":"https://doi.org/10.35848/1347-4065/ad70be","url":null,"abstract":"High-purity ternary titanium–niobium nitride nanoparticles were prepared by an induction thermal plasma. Metallic Ti and Nb powders served as raw materials. Molar fractions of Nb/(Ti+Nb) were set at various levels including 0, 0.25, 0.5, 0.75, and 1. Ammonia was introduced from the bottom into the plasma equipment as a quench gas. Nanoparticles crystallized in a cubic rock salt structure in the crystallographic space group <italic toggle=\"yes\">Fm</italic>-3<italic toggle=\"yes\">m</italic>. All nanoparticles exhibited similar morphology. The average particle size across all samples is approximately 10–14 nm. Elements Ti, Nb, and N are almost uniformly distributed in the nanoparticles. Investigations into the formation mechanism were conducted by examining nucleation temperature and thermodynamic analysis. Ternary titanium–niobium nitride nanoparticles form rapidly through nucleation, condensation, and coagulation with a nitridation reaction. Induction thermal plasma proves to be a highly efficient method for synthesizing ternary titanium–niobium nitride nanoparticles.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"423 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Aphayvong, K. Takaki, N. Fujimura, T. Yoshimura
{"title":"Enhancement of the piezoelectric properties of (100) BiFeO3 films on Si by all-sputtered epitaxial growth","authors":"S. Aphayvong, K. Takaki, N. Fujimura, T. Yoshimura","doi":"10.35848/1347-4065/ad6d74","DOIUrl":"https://doi.org/10.35848/1347-4065/ad6d74","url":null,"abstract":"The epitaxial growth of perovskite-type ferroelectric thin films on Si substrates is expected to be a method that dramatically improves the electrical properties, including the piezoelectricity. Here, we report the epitaxial growth of all films from the buffer layer to the ferroelectric layer in a single sputtering chamber. This achievement was driven by the use of the TiN buffer layer and the search for adhesion layers to improve the low adhesion between Pt and TiN. As a demonstration of the epitaxial growth of ferroelectric films, (100) BiFeO<sub>3</sub> films were fabricated using the biaxial combinatorial method. The films exhibited a crystal structure and electrical properties different from epitaxial films grown on oxide single crystals and oriented films. Under optimized conditions, the films showed well-developed polarization electric-field properties and a transverse piezoelectric constant <italic toggle=\"yes\">e</italic>\u0000<sub>31,f</sub> ∼ −6.0 C m<sup>−2</sup>.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":"14 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142218101","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}