We report a novel self-organized approach for the controllable placement of paired Ge quantum dots (QDs) along each sidewall edge of poly-Si ridges by simply thermally oxidizing spacer layers of poly-SiGe and Si3N4 that conformally encapsulate the poly-Si ridges. Additionally, controllable diameters ranging from 20−50 nm and precise location of paired Ge QDs are enabled by adjusting the thickness of poly-SiGe spacer layers in combination with specific processing conditions. These conditions include the subsequent lithographic patterning through direct etch-back for forming spacer stripes and spacer islands. The spacing between paired Ge QDs across the ridge is essentially determined by the width of the patterned poly-Si ridge. Inter-QD spacings along the sidewall of the poly-Si ridge are a consequence of heterogeneous nucleation and Ostwald Ripening.

中文翻译：

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通过设计多晶硅锗间隔结构的热氧化协调和同时形成成对的锗量子点

我们报告了一种新颖的自组织方法，用于通过简单地热氧化共形封装多晶硅脊的多晶硅锗和氮化硅隔离层，沿着多晶硅脊的每个侧壁边缘可控地放置成对的锗量子点（QD）。此外，通过结合特定的加工条件调整多晶硅锗间隔层的厚度，可以实现 20-50 nm 的可控直径和成对 Ge QD 的精确定位。这些条件包括通过直接回蚀形成间隔条和间隔岛的后续光刻图案化。穿过脊的成对 Ge QD 之间的间距基本上由图案化的多晶硅脊的宽度决定。