We investigate the effects of oxygen on the thermal diffusion of germanium atoms, implanted inside a thermally grown SiO₂ layer, during high temperature processes (1100 °C, 60 min). The impact of the presence of oxygen on Ge diffusion is studied as a function of its origin, as it can come either from the annealing atmosphere (extrinsic source) or from the SiO₂ matrix itself (intrinsic source). ¹⁸O labeling of the oxygen either in the annealing atmosphere or in the silica substrate, together with an isotopically sensitive ion beam analysis, shows a clear oxygen-dependence in germanium diffusion. This is especially so when oxygen is present in the annealing atmosphere, where it is responsible for an enhancement of germanium out-diffusion and redistribution into several peaks during annealing, through the formation of GeO molecules. A new three-process model is proposed to explain the impact of a contaminated atmosphere on the Ge redistribution. This is notably shown that a third Ge peak arises at the sample surface when the annealing atmosphere is contaminated by oxygen. This peak formation is explained by the oxidation of Ge present at the vicinity of the surface by oxygen coming from the annealing atmosphere. This is also shown that O₂ molecules can diffuse in depth, with a coefficient of diffusion ${\mathrm{D}}_{{\mathrm{O}}_2}\sim {10}^{-9}\mathrm{c}{\mathrm{m}}^2/\mathrm{s}$, until the densities of Ge and irradiation-induced defects increase, causing the progressive oxidation of Ge in depth and the restoration of the SiO₂ stoichiometry.

中文翻译：

---

SiO2/Si 薄膜中锗扩散的 18O(p,α)15N 同位素示踪

我们研究了在高温工艺（1100 °C，60 分钟）期间，氧对注入热生长的 SiO ₂层内的锗原子热扩散的影响。氧的存在对 Ge 扩散的影响作为其来源的函数进行研究，因为它可以来自退火气氛（外源）或来自 SiO ₂基体本身（本源）。¹⁸在退火气氛中或在二氧化硅衬底中氧的 O 标记，连同同位素敏感的离子束分析，显示出锗扩散中明显的氧依赖性。当退火气氛中存在氧气时尤其如此，在退火过程中，通过形成 GeO 分子，它负责增强锗的向外扩散和重新分布到几个峰中。提出了一个新的三过程模型来解释受污染的大气对 Ge 重新分布的影响。值得注意的是，当退火气氛被氧气污染时，第三个 Ge 峰出现在样品表面。这种峰的形成是由于存在于表面附近的 Ge 被来自退火气氛的氧气氧化了。这也表明 O_2个分子可以深度扩散，具有扩散系数${\mathrm{D}}_{{\mathrm{哦}}_2}～{10}^{-9}\mathrm{C}{\mathrm{米}}^2/\mathrm{秒}$，直到 Ge 的密度和辐射诱导的缺陷增加，导致 Ge 深度氧化和 SiO ₂化学计量的恢复。