{"title":"Ta5+-substitution effects on crystal structure and ferroelectric property in HfO2-based films","authors":"Yoshiki Maekawa, Takanori Mimura, Yoshiyuki Inaguma, Hiroshi Uchida, Yuxian Hu, Kazuki Okamoto and Hiroshi Funakubo","doi":"10.35848/1347-4065/ad6fa9","DOIUrl":null,"url":null,"abstract":"To investigate the Ta5+-substitution effects on crystal structure and ferroelectric property in HfO2-based films, TaxHf1−xO2+δ films with various film thicknesses and Ta content were prepared. The ferroelectric orthorhombic phase was formed in a wide film thickness range of 20–100 nm while in a narrow composition range of x = 0.10–0.14. These thickness-insensitive and composition-sensitive characteristics of Ta5+-substituted HfO2 film are similar to Y3+ rather than Zr4+. The X-ray photoelectron spectroscopy measurement suggests that the ionic state of Ta is not reduced and TaxHf1−xO2+δ film has an excess oxygen state. The excess oxygen may consist of a combination of oxygen vacancies and more interstitial oxygens. These defects facilitate the formation of the ferroelectric phasebut also decrease the breakdown voltage and increase the leakage current in Ta5+-substituted HfO2 films. On the other hand, the generation of excess oxygen indicates the possibility of controlling oxygen vacancies which deteriorate fatigue and retention properties.","PeriodicalId":14741,"journal":{"name":"Japanese Journal of Applied Physics","volume":null,"pages":null},"PeriodicalIF":1.5000,"publicationDate":"2024-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Japanese Journal of Applied Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.35848/1347-4065/ad6fa9","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, APPLIED","Score":null,"Total":0}
引用次数: 0
Abstract
To investigate the Ta5+-substitution effects on crystal structure and ferroelectric property in HfO2-based films, TaxHf1−xO2+δ films with various film thicknesses and Ta content were prepared. The ferroelectric orthorhombic phase was formed in a wide film thickness range of 20–100 nm while in a narrow composition range of x = 0.10–0.14. These thickness-insensitive and composition-sensitive characteristics of Ta5+-substituted HfO2 film are similar to Y3+ rather than Zr4+. The X-ray photoelectron spectroscopy measurement suggests that the ionic state of Ta is not reduced and TaxHf1−xO2+δ film has an excess oxygen state. The excess oxygen may consist of a combination of oxygen vacancies and more interstitial oxygens. These defects facilitate the formation of the ferroelectric phasebut also decrease the breakdown voltage and increase the leakage current in Ta5+-substituted HfO2 films. On the other hand, the generation of excess oxygen indicates the possibility of controlling oxygen vacancies which deteriorate fatigue and retention properties.
期刊介绍:
The Japanese Journal of Applied Physics (JJAP) is an international journal for the advancement and dissemination of knowledge in all fields of applied physics. JJAP is a sister journal of the Applied Physics Express (APEX) and is published by IOP Publishing Ltd on behalf of the Japan Society of Applied Physics (JSAP).
JJAP publishes articles that significantly contribute to the advancements in the applications of physical principles as well as in the understanding of physics in view of particular applications in mind. Subjects covered by JJAP include the following fields:
• Semiconductors, dielectrics, and organic materials
• Photonics, quantum electronics, optics, and spectroscopy
• Spintronics, superconductivity, and strongly correlated materials
• Device physics including quantum information processing
• Physics-based circuits and systems
• Nanoscale science and technology
• Crystal growth, surfaces, interfaces, thin films, and bulk materials
• Plasmas, applied atomic and molecular physics, and applied nuclear physics
• Device processing, fabrication and measurement technologies, and instrumentation
• Cross-disciplinary areas such as bioelectronics/photonics, biosensing, environmental/energy technologies, and MEMS