{"title":"Sputtering and structural modifications induced in silicon dioxide (SiO<sub>2</sub>) thin films under (10–40 MeV) Au<sup>q+</sup> heavy ion irradiation","authors":"Ster Mammeri, Mhamed Salhi, Abir Boubir, Mandla Msimanga, Christopher Mtshali, Mlungisi Nkosi","doi":"10.1002/sia.7257","DOIUrl":null,"url":null,"abstract":"Surface sputtering and structural modifications induced in silicon dioxide thin films (SiO 2 /Si) deposited on silicon substrates and irradiated by swift (10–40 MeV) heavy Au q+ (q = +4, +6, +7, and +9) ions were investigated by grazing‐incidence X‐ray diffraction (GIXRD) spectroscopy, Rutherford backscattering (RBS) spectrometry and time‐of‐flight elastic recoil detection (ToF‐ERDA) technique. The GIXRD analysis of the as‐deposited and irradiated samples revealed increasing structural modifications of the SiO 2 thin films under Au q+ ion impacts with increasing ion‐beam energy. The changes consisted of decreased grain sizes with increased strain accompanied by a phase transformation from crystalline to amorphous films. RBS analysis showed a decrease in the mean stoichiometric (O/Si) ratio from (2.2 ± 0.1) to (1.7 ± 0.1), due to preferential sputtering of oxygen, as the incident ion energy increased. The obtained RBS‐results were then completed by those of ToF‐ERDA analysis technique using a 40 MeV Au 9+ heavy ion beam. The preferential sputtering yield ratios (Y Si /Y O ) were determined experimentally both versus electronic stopping power and ion fluence. The obtained results were then compared to numerical values derived from the inelastic thermal spike (i‐TS) model, Sigmund's analytical formula and SRIM simulation code. A good agreement was observed between the measured preferential sputtering data and the i‐TS calculated values, when considering both nuclear elastic and electronic inelastic collision mechanisms. Besides, a close correlation is observed between the electronic stopping power dependent measured sputtering yields and the XRD peak intensity degradation per unit fluence. These observations suggest that the same mechanism of MeV heavy ion‐irradiation induced extended atomic disordering, occurs both in the case of structural modifications and surface sputtering. Finally, the obtained experimental results are discussed on the basis of the i‐TS model.","PeriodicalId":22062,"journal":{"name":"Surface and Interface Analysis","volume":null,"pages":null},"PeriodicalIF":1.6000,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Surface and Interface Analysis","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1002/sia.7257","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Surface sputtering and structural modifications induced in silicon dioxide thin films (SiO 2 /Si) deposited on silicon substrates and irradiated by swift (10–40 MeV) heavy Au q+ (q = +4, +6, +7, and +9) ions were investigated by grazing‐incidence X‐ray diffraction (GIXRD) spectroscopy, Rutherford backscattering (RBS) spectrometry and time‐of‐flight elastic recoil detection (ToF‐ERDA) technique. The GIXRD analysis of the as‐deposited and irradiated samples revealed increasing structural modifications of the SiO 2 thin films under Au q+ ion impacts with increasing ion‐beam energy. The changes consisted of decreased grain sizes with increased strain accompanied by a phase transformation from crystalline to amorphous films. RBS analysis showed a decrease in the mean stoichiometric (O/Si) ratio from (2.2 ± 0.1) to (1.7 ± 0.1), due to preferential sputtering of oxygen, as the incident ion energy increased. The obtained RBS‐results were then completed by those of ToF‐ERDA analysis technique using a 40 MeV Au 9+ heavy ion beam. The preferential sputtering yield ratios (Y Si /Y O ) were determined experimentally both versus electronic stopping power and ion fluence. The obtained results were then compared to numerical values derived from the inelastic thermal spike (i‐TS) model, Sigmund's analytical formula and SRIM simulation code. A good agreement was observed between the measured preferential sputtering data and the i‐TS calculated values, when considering both nuclear elastic and electronic inelastic collision mechanisms. Besides, a close correlation is observed between the electronic stopping power dependent measured sputtering yields and the XRD peak intensity degradation per unit fluence. These observations suggest that the same mechanism of MeV heavy ion‐irradiation induced extended atomic disordering, occurs both in the case of structural modifications and surface sputtering. Finally, the obtained experimental results are discussed on the basis of the i‐TS model.
期刊介绍:
Surface and Interface Analysis is devoted to the publication of papers dealing with the development and application of techniques for the characterization of surfaces, interfaces and thin films. Papers dealing with standardization and quantification are particularly welcome, and also those which deal with the application of these techniques to industrial problems. Papers dealing with the purely theoretical aspects of the technique will also be considered. Review articles will be published; prior consultation with one of the Editors is advised in these cases. Papers must clearly be of scientific value in the field and will be submitted to two independent referees. Contributions must be in English and must not have been published elsewhere, and authors must agree not to communicate the same material for publication to any other journal. Authors are invited to submit their papers for publication to John Watts (UK only), Jose Sanz (Rest of Europe), John T. Grant (all non-European countries, except Japan) or R. Shimizu (Japan only).