Epitaxial Ge-on-Si possesses a high density of threading dislocations (TDs) due to the lattice mismatch and difference in thermal expansion coefficient. By employing the lattice distortion at the TDs, we demonstrate that penetrating pores along TDs can be formed in both - and -type heteroepitaxial Ge layers through a preferential etching. It has been found that the preferential etching at TD sites takes place in the porosification process of Ge-on-Si samples and is independent of the doping type and concentration. The penetrating pores follow the path of the TD lines and can penetrate the entire Ge layer of 1.3 μm to further porosificate the Si substrate. The effects of anodic current density and total etching duration have been thoroughly investigated on forming penetrating pores at TD sites. The dissolution mechanism in the porosification process has been revealed by dissolution valence calculation and recorded potential curves. Our findings shed light on Ge perforation in both - and -type Ge-on-Si and show great potential in Si-based integrated photonics and microelectronics.

中文翻译：

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通过沿着螺纹位错优先蚀刻在外延 Ge-on-Si 中制造穿透孔


由于晶格失配和热膨胀系数差异，外延硅基Ge具有高密度的穿透位错（TD）。通过利用TD处的晶格畸变，我们证明通过优先蚀刻，可以在-和-型异质外延Ge层中形成沿着TD的穿透孔。研究发现，TD位点的优先蚀刻发生在Ge-on-Si样品的多孔化过程中，并且与掺杂类型和浓度无关。穿透孔沿着TD线的路径，可以穿透整个1.3μm的Ge层，从而进一步使Si衬底多孔化。阳极电流密度和总蚀刻持续时间对在 TD 位置形成穿透孔的影响进行了深入研究。通过溶解价计算和记录的电位曲线揭示了多孔化过程中的溶解机制。我们的研究结果揭示了 和 型 Ge-on-Si 中的 Ge 穿孔，并显示出在硅基集成光子学和微电子学中的巨大潜力。