Abstract Thick Ge layers grown on Si(0 0 1) are handy for the production of GeOI wafers, as templates for the epitaxy of III-V and GeSn-based heterostructures and so on. Perfecting their crystalline quality would enable to fabricate suspended Ge micro-bridges with extremely high levels of tensile strain (for mid IR lasers). In this study, we have used a low temperature (400 °C)/high temperature (750 °C) approach to deposit with GeH 4 various thickness Ge layers in the 0.5 µm – 5 µm range. They were submitted afterwards to short duration thermal cycling under H 2 (in between 750 °C and 875–890 °C) to lower the Threading Dislocation Density (TDD). Some of the thickest layers were partly etched at 750 °C with gaseous HCl to recover wafer bows compatible with device processing later on. X-ray Diffraction (XRD) showed that the layers were slightly tensile-strained, with a 104.5–105.5% degree of strain relaxation irrespective of the thickness. The surface was cross-hatched, with a roughness slightly decreasing with the thickness, from 2.0 down to 0.8 nm. The TDD (from Omega scans in XRD) decreased from 8 × 10 7 cm −2 down to 10 7 cm −2 as the Ge layer thickness increased from 0.5 up to 5 µm. The lack of improvement when growing 5 µm thick layers then etching a fraction of them with HCl over same thickness layers grown in a single run was at variance with Thin Solid Films 520, 3216 (2012). Low temperature HCl defect decoration confirmed those findings, with (i) a TDD decreasing from slightly more 10 7 cm −2 down to 5 × 10 6 cm −2 as the Ge layer thickness increased from 1.3 up to 5 µm and (ii) no TDD hysteresis between growth and growth then HCl etch-back.

中文翻译：

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用于在 Si 上生产 Ge 应变松弛缓冲液的生长/回蚀技术的评估

摘要 在 Si(0 0 1) 上生长的厚 Ge 层可方便地用于生产 GeOI 晶片，作为 III-V 族和 GeSn 基异质结构的外延模板等。完善其晶体质量将能够制造具有极高拉伸应变水平的悬浮锗微桥（用于中红外激光器）。在本研究中，我们使用低温 (400 °C)/高温 (750 °C) 方法在 0.5 µm – 5 µm 范围内沉积 GeH 4 各种厚度的 Ge 层。随后将它们置于 H 2 下（在 750°C 和 875-890°C 之间）进行短期热循环，以降低螺纹位错密度 (TDD)。一些最厚的层在 750 °C 下用气态 HCl 进行部分蚀刻，以恢复与以后器件处理兼容的晶圆弓。X 射线衍射 (XRD) 表明，无论厚度如何，这些层都具有轻微的拉伸应变，具有 104.5-105.5% 的应变松弛度。表面是交叉阴影线，粗糙度随着厚度的增加而略有下降，从 2.0 到 0.8 nm。随着Ge层厚度从0.5增加到5μm，TDD（来自XRD中的Omega扫描）从8×10 7 cm -2 下降到10 7 cm -2 。生长 5 µm 厚的层，然后在单次运行中生长的相同厚度层上用 HCl 蚀刻其中的一小部分时缺乏改进，这与 Thin Solid Films 520, 3216 (2012) 不同。低温 HCl 缺陷装饰证实了这些发现，（i）随着 Ge 层厚度从 1 增加，TDD 从略高于 10 7 cm -2 下降到 5 × 10 6 cm -2。