High aspect ratio Si micro-holes formed by wet etching using Pt needles
High aspect ratio Si micro-holes formed by wet etching using Pt needles
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DOI：
10.1088/2053-1591/2/7/075901
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发表时间：
2015-07
影响因子：
2.3
通讯作者：
K. Imamura;T. Akai;H. Kobayashi
中科院分区：
文献类型：
--
作者：
K. Imamura;T. Akai;H. Kobayashi
利用Pt针的催化活性可以形成具有高纵横比的Si微孔，即，Pt针与浸入HF加H2 O2溶液中的Si晶片的接触。在电阻率为10 Ωcm的p-Si中，Pt针的形状被精确地转移到Si衬底上，并实现了8的深宽比。高分辨率TEM观察的Si微孔的侧壁表明，它们是通过形成的纳米晶Si层，然后通过其溶解形成的。通过比较n-Si和p-Si中形成的微孔，可以明显看出，形成纳米晶Si层的注入空穴的扩散影响微孔的形状。在n-Si的情况下，由于溶液的氧化还原电位与Si费米能级之间的差异导致的Si能带弯曲，注入的空穴扩散到Si/溶液界面，并在与Pt针的非接触区域引起Si溶解反应。
Si micro-holes with a high aspect ratio can be formed by use of catalytic activity of Pt needles, i.e., contact of Pt needles with Si wafers immersed in an HF plus H2O2 solution. In the case of p-Si with ∼10 Ωcm resistivity, the shape of the Pt needle is accurately transferred to the Si substrate, and the aspect ratio of 8 is achieved. High-resolution TEM observations of the sidewall of the Si micro-holes show that they are formed through formation of a nanocrystalline Si layer followed by its dissolution. By comparing micro-holes formed in n-Si and in p-Si, it becomes obvious that diffusion of injected holes, which form the nanocrystalline Si layer, affects the shape of micro-holes. In the case of n-Si, injected holes diffuse to the Si/solution interface due to the Si band-bending resulting from the difference between the redox potential of the solution and the Si Fermi level, and cause an Si dissolution reaction at non-contact regions with the Pt needle.