Hydrogen behavior in tantalum and tantalum oxide thin films was examined using the in situ oxidation secondary ion mass spectrometry (in situ oxidation SIMS) method previously developed by the authors. Oxidation of Ta films by the introduction of O2 into the sputter deposition chamber immediately after film growth was found to reduce the amount of H absorbed in the Ta films by 2.7 times for samples exposed to lab air at ambient temperature; the difference increased to 4.8 times for samples exposed to air at 300 °C. From these results, it is apparent that Ta absorbs H from H2 or through reaction with H2O in air and that an oxide film “cap” largely stymies H absorption. To investigate the redistribution of hydrogen during oxidation of Ta, sputtered Ta films were implanted with deuterium, and some were subsequently anodized. In situ oxidation SIMS analysis of Ta2O5/Ta bilayer films created by anodization of deuterium (D)-implanted Ta films revealed no deuterium in the upper Ta2O5 portion; however, the total amount of deuterium detected in the underlying Ta layer of the anodized samples was close to the total amount of deuterium measured in the Ta layer of a nonanodized, D-implanted Ta film. These results indicate that during anodization, D is concentrated in the residual metal region as it is excluded from the growing oxide film. Ab initio calculations of H interstitial defects in Ta and Ta2O5 revealed that the heat of formation, ΔH, for H interstitial defects in Ta is 1.31 eV lower than that of Ta2O5; this result is consistent with the observed H blocking property of oxide films and the observed redistribution of D from oxide to metal during anodization.

中文翻译：

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通过原位氧化 SIMS 和 ab initio 计算研究了钽和氧化钽系统中氢的吸收、放电和内部分配行为

使用作者先前开发的原位氧化二次离子质谱（原位氧化 SIMS）方法检查了钽和氧化钽薄膜中的氢行为。发现在薄膜生长后立即将 O2 引入溅射沉积室来氧化 Ta 薄膜，对于暴露在环境温度下的实验室空气中的样品，Ta 薄膜中吸收的 H 量减少了 2.7 倍；对于暴露在 300 °C 空气中的样品，差异增加到 4.8 倍。从这些结果可以看出，Ta 从 H2 中或通过与空气中的 H2O 反应吸收 H，并且氧化膜“盖帽”在很大程度上阻碍了 H 的吸收。为了研究 Ta 氧化过程中氢的重新分布，溅射的 Ta 膜被注入氘，一些随后被阳极氧化。通过对注入氘 (D) 的 Ta 薄膜进行阳极氧化而产生的 Ta2O5/Ta 双层薄膜的原位氧化 SIMS 分析表明，在上部的 Ta2O5 部分中没有氘；然而，在阳极氧化样品的底层 Ta 层中检测到的氘总量接近在未阳极化、D 注入的 Ta 膜的 Ta 层中测得的氘总量。这些结果表明，在阳极氧化过程中，D 集中在残留金属区域，因为它被排除在生长的氧化膜之外。Ta 和 Ta2O5 中 H 间隙缺陷的从头算计算表明，Ta 中 H 间隙缺陷的形成热 ΔH 比 Ta2O5 低 1.31 eV；该结果与观察到的氧化膜的 H 阻挡特性和观察到的 D 在阳极氧化过程中从氧化物到金属的重新分布是一致的。