{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T15:00:32Z","timestamp":1785423632680,"version":"3.56.0"},"reference-count":59,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T00:00:00Z","timestamp":1785369600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["0000205"],"award-info":[{"award-number":["0000205"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000780","name":"European Commission","doi-asserted-by":"publisher","award":["M2 0000006"],"award-info":[{"award-number":["M2 0000006"]}],"id":[{"id":"10.13039\/501100000780","id-type":"DOI","asserted-by":"publisher"}]},{"award":["0000205"],"award-info":[{"award-number":["0000205"]}],"id":[{"id":"https:\/\/ror.org\/00k4n6c32","id-type":"ROR","asserted-by":"publisher"}]},{"award":["M2 0000006"],"award-info":[{"award-number":["M2 0000006"]}],"id":[{"id":"https:\/\/ror.org\/00k4n6c32","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Micromachines"],"abstract":"<jats:p>This article reviews the reactive magnetron sputtering of piezoelectric Aluminium Nitride (AlN) thin films, with a focus on process parameter optimisation and system-level deposition challenges. AlN is a leading material for MEMS and RF applications owing to its c-axis (002) orientation, high acoustic velocity, wide bandgap (\u223c6.2 eV), and CMOS compatibility. We review the influence of sputtering power, nitrogen flow ratio, substrate temperature, and target-to-substrate distance on crystallographic quality and document practical hardware challenges, including vacuum leakage, grounding faults, target erosion, and mass flow controller drift, that critically affect reproducibility but are systematically underreported in the literature. A perspective is provided on emerging application domains where optimised AlN films address current performance gaps, including next-generation RF\/telecom systems towards 6G and Future Networks, harsh environment sensing and actuation, biomedical ultrasound, and IoT energy harvesting. The complementarity between AlN and Silicon Carbide (SiC) is discussed for high-temperature, high-power, and radiation-hard MEMS, where AlN\/SiC heterostructures combine the piezoelectric activity of AlN with the mechanical and chemical robustness of SiC. It also incorporates a discussion of dopant- and heteroepitaxy-based AlN engineering, AlN deposition on a wider range of substrates, the role of seed and electrode underlayers, and pulsed-DC sputtering as a third power supply mode alongside RF and conventional DC.<\/jats:p>","DOI":"10.3390\/mi17080919","type":"journal-article","created":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:55:11Z","timestamp":1785419711000},"page":"919","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Sputtered Piezoelectric AlN Thin Films: Parameter Optimisation, Deposition Challenges, and Emerging Perspectives\u2014A Review"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-2606-5902","authenticated-orcid":false,"given":"Rangaraajan","family":"Muralidaran","sequence":"first","affiliation":[{"name":"Department of Electronics and Communication Engineering, National Institute of Technology Warangal, Hanamkonda 506004, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9385-933X","authenticated-orcid":false,"given":"Paritosh","family":"Dubey","sequence":"additional","affiliation":[{"name":"Advanced Materials and Corrosion Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India"},{"name":"Engineering Sciences, Academy of Scientific and Innovative Research, Ghaziabad 201002, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3841-4332","authenticated-orcid":false,"given":"Kuldeep Singh","family":"Gour","sequence":"additional","affiliation":[{"name":"Advanced Materials and Corrosion Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India"},{"name":"Engineering Sciences, Academy of Scientific and Innovative Research, Ghaziabad 201002, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shuvam","family":"Pawar","sequence":"additional","affiliation":[{"name":"Department of Electronics and Communication Engineering, National Institute of Technology Warangal, Hanamkonda 506004, India"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2223-8637","authenticated-orcid":false,"given":"Vinod","family":"Belwanshi","sequence":"additional","affiliation":[{"name":"Engineering Sciences, Academy of Scientific and Innovative Research, Ghaziabad 201002, India"},{"name":"Materials Engineering Division, CSIR-National Metallurgical Laboratory, Jamshedpur 831007, India"},{"name":"School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6462-4814","authenticated-orcid":false,"given":"Jacopo","family":"Iannacci","sequence":"additional","affiliation":[{"name":"Center for Sensors and Devices (SD), Fondazione Bruno Kessler (FBK), 38123 Trento, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,7,30]]},"reference":[{"key":"ref_1","unstructured":"Carter, R., and Kensley, R. (2025, July 18). Introduction to Piezoelectric Transducers. Available online: https:\/\/piezo.com\/pages\/piezoelectric-transducers-abstract."},{"key":"ref_2","unstructured":"Bhattacharyya, A.S., Kumar, R., Raj, V., Shrinidhi, S., Suman, S., Shah, A., and Kumar, R.P. (2016). Some aspects of epitaxial thin film growth. arXiv."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"55428","DOI":"10.1109\/ACCESS.2022.3176348","article-title":"Review and Perspectives of Micro\/Nano Technologies as Key-Enablers of 6G","volume":"10","author":"Iannacci","year":"2022","journal-title":"IEEE Access"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1109\/JPROC.2022.3223791","article-title":"A Perspective Vision of Micro\/Nano Systems and Technologies as Enablers of 6G, Super-IoT, and Tactile Internet","volume":"111","author":"Iannacci","year":"2023","journal-title":"Proc. IEEE"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Zhang, Q., Liu, Y., Li, H., Wang, J., Wang, Y., Cheng, F., Han, H., and Zhang, P. (2024). A Review of SiC Sensor Applications in High-Temperature and Radiation Extreme Environments. Sensors, 24.","DOI":"10.3390\/s24237731"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Guo, X., Xun, Q., Li, Z., and Du, S. (2019). Silicon Carbide Converters and MEMS Devices for High-temperature Power Electronics: A Critical Review. Micromachines, 10.","DOI":"10.3390\/mi10060406"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"Y10.61","DOI":"10.1557\/PROC-798-Y10.61","article-title":"MBE Grown AlN Films on SiC for Piezoelectric MEMS Sensors","volume":"798","author":"Doppalapudi","year":"2004","journal-title":"MRS Online Proc. Libr."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"550","DOI":"10.3390\/s130100550","article-title":"Lamb Waves Propagation along 3C-SiC\/AlN Membranes for Application in Temperature-Compensated, High-Sensitivity Gravimetric Sensors","volume":"13","author":"Caliendo","year":"2013","journal-title":"Sensors"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Wang, W.Z., Ruan, Y., and You, Z. (2017). AlN\/6H-SiC SAW resonator for high temperature wireless SAW sensor. Proceedings of the 2017 19th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), IEEE.","DOI":"10.1109\/TRANSDUCERS.2017.7994205"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"114379","DOI":"10.1016\/j.sna.2023.114379","article-title":"Surface acoustic wave temperature sensor based on Pt\/AlN\/4H-SiC structure for high-temperature environments","volume":"357","author":"Yang","year":"2023","journal-title":"Sens. Actuators A Phys."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1186\/s11671-023-03779-8","article-title":"A review of piezoelectric MEMS sensors and actuators for gas detection application","volume":"18","author":"Khir","year":"2023","journal-title":"Discov. Nano"},{"key":"ref_12","doi-asserted-by":"crossref","unstructured":"Chen, S., and You, Z. (2016). Modeling and Experimental Analysis on the Temperature Response of AlN-Film Based SAWRs. Sensors, 16.","DOI":"10.3390\/s16081205"},{"key":"ref_13","unstructured":"Cunha, C.L.A., Pimenta, T.C., and Fraga, M.A. (2022). Development and Applications of Aluminum Nitride Thin Film Technology. Thin Film Deposition\u2014Fundamentals, Processes, and Applications, IntechOpen."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1007\/s00339-021-05166-5","article-title":"Study on optimizing c-axis oriented AlN thin film for piezoelectric sensing applications controlling the sputtering process parameters","volume":"128","author":"Vanamoorthy","year":"2022","journal-title":"Appl. Phys. A"},{"key":"ref_15","doi-asserted-by":"crossref","unstructured":"Khan, M., Nowsherwan, G.A., Shah, A.A., Riaz, S., Riaz, M., Chandio, A.D., Shah, A.K., Channa, I.A., Hussain, S.S., and Ali, R. (2022). A Study of the Structural and Surface Morphology and Photoluminescence of Ni-Doped AlN Thin Films Grown by Co-Sputtering. Nanomaterials, 12.","DOI":"10.3390\/nano12213919"},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Bairagi, S., J\u00e4rrendahl, K., Eriksson, F., Hultman, L., Birch, J., and Hsiao, C.-L. (2020). Glancing Angle Deposition and Growth Mechanism of Inclined AlN Nanostructures Using Reactive Magnetron Sputtering. Coatings, 10.","DOI":"10.3390\/coatings10080768"},{"key":"ref_17","doi-asserted-by":"crossref","unstructured":"Iqbal, A., and Mohd-Yasin, F. (2018). Reactive Sputtering of Aluminum Nitride (002) Thin Films for Piezoelectric Applications: A Review. Sensors, 18.","DOI":"10.3390\/s18061797"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/S0079-6816(99)00021-0","article-title":"Trends in sputtering","volume":"64","author":"Smentkowski","year":"2000","journal-title":"Prog. Surf. Sci."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"159","DOI":"10.1016\/S0042-207X(99)00189-X","article-title":"Magnetron sputtering: A review of recent developments and applications","volume":"56","author":"Kelly","year":"2000","journal-title":"Vacuum"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1049\/nde2.12076","article-title":"A strong dependence of sputtering power on c-axis oriented aluminium nitride on Si (111): A structural and electrical study","volume":"7","author":"Sanjeeva","year":"2024","journal-title":"IET Nanodielectrics"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1039","DOI":"10.1016\/j.materresbull.2010.05.035","article-title":"Synthesis of c-axis oriented AlN thin films on different substrates: A review","volume":"45","author":"Iriarte","year":"2010","journal-title":"Mater. Res. Bull."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1195","DOI":"10.1016\/j.apsusc.2015.07.059","article-title":"Electric and pyroelectric properties of AlN thin films deposited by reactive magnetron sputtering on Si substrate","volume":"353","author":"Stan","year":"2015","journal-title":"Appl. Surf. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2201197","DOI":"10.1002\/aelm.202201197","article-title":"Ab-initio Prediction of Ultra-Wide Band Gap BxAl1\u2212xN Materials","volume":"9","author":"Milne","year":"2023","journal-title":"Adv. Electron. Mater."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"2347","DOI":"10.1515\/nanoph-2021-0130","article-title":"Aluminium nitride integrated photonics: A review","volume":"10","author":"Li","year":"2021","journal-title":"Nanophotonics"},{"key":"ref_25","unstructured":"Martin, P.M. (2010). Sputter Deposition Processes. Handbook of Deposition Technologies for Films and Coatings, William Andrew. [3rd ed.]."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"3668","DOI":"10.1007\/s12598-020-01675-z","article-title":"Substrate angle-induced fully c-axis orientation of AlN films deposited by off-normal DC sputtering method","volume":"40","author":"Xie","year":"2021","journal-title":"Rare Met."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"109","DOI":"10.1016\/j.vacuum.2017.02.018","article-title":"Balanced magnetic field in magnetron sputtering systems","volume":"139","author":"Golosov","year":"2017","journal-title":"Vacuum"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Zhou, W.-Y., Chen, H.-F., Tseng, X.-L., Lo, H.-H., Wang, P.J., Jiang, M.-Y., Fuh, Y.-K., and Li, T.T. (2023). Impact of Pulse Parameters of a DC Power Generator on the Microstructural and Mechanical Properties of Sputtered AlN Film with In-Situ OES Data Analysis. Materials, 16.","DOI":"10.3390\/ma16083015"},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Sandager, M.K., Kjelde, C., and Popok, V. (2022). Growth of Thin AlN Films on Si Wafers by Reactive Magnetron Sputtering: Role of Processing Pressure, Magnetron Power and Nitrogen\/Argon Gas Flow Ratio. Crystals, 12.","DOI":"10.3390\/cryst12101379"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"109304","DOI":"10.1016\/j.mssp.2025.109304","article-title":"Multipath-induced c-axis orientation of aluminum nitride films deposited using direct-current magnetron sputtering","volume":"189","author":"Zhu","year":"2025","journal-title":"Mater. Sci. Semicond. Process."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"184525","DOI":"10.1016\/j.jallcom.2025.184525","article-title":"Wafer-scale fabrication and growth mechanism investigation of silicon-based AlN piezoelectric films with c-axis orientation by magnetron sputtering","volume":"1044","author":"Zheng","year":"2025","journal-title":"J. Alloys Compd."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.jcrysgro.2012.10.008","article-title":"Influence of sputtering parameters on structures and residual stress of AlN films deposited by DC reactive magnetron sputtering at room temperature","volume":"363","author":"Liu","year":"2013","journal-title":"J. Cryst. Growth"},{"key":"ref_33","doi-asserted-by":"crossref","unstructured":"Liu, W.-S., Gururajan, B., Wu, S.-H., Huang, L.-C., Chi, C.-K., Jiang, Y.-L., and Kuo, H.-C. (2022). Optimal Growth Conditions for Forming c-Axis (002) Aluminum Nitride Thin Films as a Buffer Layer for Hexagonal Gallium Nitride Thin Films Produced with In Situ Continual Radio Frequency Sputtering. Micromachines, 13.","DOI":"10.3390\/mi13091546"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"459","DOI":"10.1016\/j.jcrysgro.2008.09.046","article-title":"Influence of sputtering parameters on the crystallinity and crystal orientation of AlN layers deposited by RF sputtering using the AlN target","volume":"311","author":"Vashaei","year":"2009","journal-title":"J. Cryst. Growth"},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"282","DOI":"10.1016\/j.pnsc.2015.08.006","article-title":"Texture of the nano-crystalline AlN thin films and the growth conditions in DC magnetron sputtering","volume":"25","author":"Khan","year":"2015","journal-title":"Prog. Nat. Sci. Mater. Int."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"221","DOI":"10.1007\/BF00186189","article-title":"Effects of sputtering pressure and nitrogen concentration on the preferred orientation of AlN thin films","volume":"5","author":"Lee","year":"1994","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_37","unstructured":"Panda, P., Ramaseshan, R., Ravi, N., Mangamma, G., Jose, F., Dash, S., Suzuki, K., and Suematsu, H. (2015). Reduction of residual stress in AlN thin films synthesized by magnetron sputtering technique. arXiv."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"381","DOI":"10.1007\/s00542-010-1198-2","article-title":"Effect of substrate\u2013target distance and sputtering pressure in the synthesis of AlN thin films","volume":"17","author":"Iriarte","year":"2011","journal-title":"Microsyst. Technol."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"603","DOI":"10.1016\/j.mee.2012.05.055","article-title":"Flexible piezoelectric cantilevers fabricated on polyimide substrate","volume":"98","author":"Petroni","year":"2012","journal-title":"Microelectron. Eng."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"045005","DOI":"10.1088\/1361-665X\/aa5d99","article-title":"Enhancing the piezoelectric properties of flexible hybrid AlN materials using semi-crystalline parylene","volume":"26","author":"Jackson","year":"2017","journal-title":"Smart Mater. Struct."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"20","DOI":"10.1016\/j.matlet.2015.07.069","article-title":"Growth of AlN films as a function of temperature on Mo films","volume":"160","author":"Yang","year":"2015","journal-title":"Mater. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"345","DOI":"10.1016\/j.jcrysgro.2007.10.033","article-title":"Influence of molybdenum bottom electrodes on crystal growth of aluminum nitride thin films","volume":"310","author":"Kamohara","year":"2008","journal-title":"J. Cryst. Growth"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"593","DOI":"10.1002\/adma.200802611","article-title":"Enhancement of piezoelectric response in scandium aluminum nitride alloy thin films prepared by dual reactive cosputtering","volume":"21","author":"Akiyama","year":"2009","journal-title":"Adv. Mater."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"7520","DOI":"10.1007\/s11664-018-6695-6","article-title":"Influence of Process Parameters and Formation of Highly c-Axis Oriented AlN Thin Films on Mo by Reactive Sputtering","volume":"47","author":"Chauhan","year":"2018","journal-title":"J. Electron. Mater."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"L61","DOI":"10.1116\/1.3501117","article-title":"Sputtering of (001) AlN thin films: Control of polarity by a seed layer","volume":"28","author":"Milyutin","year":"2010","journal-title":"J. Vac. Sci. Technol. B"},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1016\/j.matchemphys.2018.08.013","article-title":"Growth assessment and scrutinize dielectric reliability of c-axis oriented insulating AlN thin films in MIM structures for microelectronics applications","volume":"219","author":"Pawar","year":"2018","journal-title":"Mater. Chem. Phys."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"242902","DOI":"10.1063\/1.5039969","article-title":"High magnetoelectric coupling in Si-integrated AlN\/NiMnIn thin film double layers at room temperature","volume":"113","author":"Pawar","year":"2018","journal-title":"Appl. Phys. Lett."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1038\/s41378-020-00183-5","article-title":"AlN MEMS filters with extremely high bandwidth widening capability","volume":"6","author":"Gao","year":"2020","journal-title":"Microsyst. Nanoeng."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1038\/s41378-024-00857-4","article-title":"Periodically poled aluminum scandium nitride bulk acoustic wave resonators and filters for communications in the 6G era","volume":"11","author":"Izhar","year":"2025","journal-title":"Microsyst. Nanoeng."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"58779","DOI":"10.1109\/ACCESS.2023.3276716","article-title":"A Review of the Recent Applications of Aluminum Nitride-Based Piezoelectric Devices","volume":"11","author":"Haider","year":"2023","journal-title":"IEEE Access"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2212538","DOI":"10.1002\/adfm.202212538","article-title":"Piezoelectric Sensors Operating at Very High Temperatures and in Extreme Environments Made of Flexible Ultrawide-Bandgap Single-Crystalline AlN Thin Films","volume":"33","author":"Kim","year":"2023","journal-title":"Adv. Funct. Mater."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"881","DOI":"10.1016\/j.apenergy.2018.07.001","article-title":"A micro-electromechanical systems based vibration energy harvester with aluminum nitride piezoelectric thin film deposited by pulsed direct-current magnetron sputtering","volume":"228","author":"He","year":"2018","journal-title":"Appl. Energy"},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"104012","DOI":"10.1088\/0960-1317\/18\/10\/104012","article-title":"The effect of the built-in stress level of AlN layers on the properties of piezoelectric vibration energy harvesters","volume":"18","author":"Karakaya","year":"2008","journal-title":"J. Micromech. Microeng."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1007\/s10854-014-2423-z","article-title":"Effects of sputtering atmosphere on the properties of c-plane ScAlN thin films prepared on sapphire substrate","volume":"26","author":"Zhang","year":"2015","journal-title":"J. Mater. Sci. Mater. Electron."},{"key":"ref_55","doi-asserted-by":"crossref","unstructured":"Umeda, K., Kawai, H., Honda, A., Akiyama, M., Kato, T., and Fukura, T. (2013). Piezoelectric properties of ScAlN thin films for piezo-MEMS devices. Proceedings of the 2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS), IEEE.","DOI":"10.1109\/MEMSYS.2013.6474347"},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"4369","DOI":"10.1038\/s41598-020-61285-8","article-title":"Polarity Inversion of Aluminum Nitride Thin Films by using Si and MgSi Dopants","volume":"10","author":"Anggraini","year":"2020","journal-title":"Sci. Rep."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"085006","DOI":"10.1088\/1361-6439\/ad5562","article-title":"A scandium doped aluminum nitride thin film bulk acoustic resonator","volume":"34","author":"Gao","year":"2024","journal-title":"J. Micromech. Microeng."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1007\/s00339-024-07960-3","article-title":"Studies on high quality GaN\/AlN deposited on glass substrates by radio-frequency reactive sputtering","volume":"130","author":"Liu","year":"2024","journal-title":"Appl. Phys. A"},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"2503827","DOI":"10.1002\/advs.202503827","article-title":"Interfacial Polarization Switching in Al0.92Sc0.08N\/GaN Heterostructures Grown by Sputter Epitaxy","volume":"12","author":"Wolff","year":"2025","journal-title":"Adv. Sci."}],"container-title":["Micromachines"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/8\/919\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T13:59:25Z","timestamp":1785419965000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-666X\/17\/8\/919"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,30]]},"references-count":59,"journal-issue":{"issue":"8","published-online":{"date-parts":[[2026,8]]}},"alternative-id":["mi17080919"],"URL":"https:\/\/doi.org\/10.3390\/mi17080919","relation":{},"ISSN":["2072-666X"],"issn-type":[{"value":"2072-666X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,30]]}}}