各向异性腐蚀制备纳米硅尖

Fabrication of Nano-Silicon-Tips Based on Anisotropic Wet Etching Technique

采用KOH溶液各向异性腐蚀单晶硅的方法制备高纵横比的纳米硅尖,研究了腐蚀溶液的浓度、添加剂异丙醇(IPA)对硅尖形状的影响。设计了硅尖制作的工艺流程,制备了形状不同、纵横比值为0.52～2.1的硅尖,并结合晶面相交模型,提出了硅尖晶面的判别方法,讨论了实验中出现的{411}和{331}晶面族两种硅尖晶面类型,实验结果和理论分析相一致。通过分析腐蚀溶液的质量分数和添加剂对{411}、{331}晶面族腐蚀速度的影响,得到了制备高纵横比纳米硅尖的工艺参数。实验结果表明:当正方形掩模边缘沿<110>晶向时,在78℃、质量分数40的KOH溶液中腐蚀硅尖,再经980℃干氧氧化3h进行锐化削尖,可制备出纵横比大于2、曲率半径达纳米量级的硅尖阵列。

The high aspect ratio nano-silicon-tips were fabricated by KOH solution with the aniso- tropic wet etching technique, and the effects of the solution concentration and the additive IPA on the shapes of silicon tips were studied. The fabrication processes for silicon tips were designed and different aspect ratio tips of 0.52 - 2. 1 were formed. Based on the intersection model of crystal planes, the identification method for crystal planes was proposed. Two crystal planes {411 } and { 331 } which appear in the experiment were discussed, the result was satisfied with the theoretical analysis. Through analyzing the effect of the solution concentration and the additive on the rapid etched crystal planes {331} and {411}, the process parameters were achieved to fabricate high aspect ratio nano-silicon-tips. The results show that the silicon tips are formed by the anisotropic etching in 40% KOH etchant at 78 ℃ and dry oxidation sharpening at 980 ℃ for 3 h with the square masks aligning to 〈110〉 direction. The aspect ratio of the tips is more than 2 and the curvature radius reaches nano level.