当前位置: X-MOL 学术J. Vac. Sci. Technol. A › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Causes of anisotropy in thermal atomic layer etching of nanostructures
Journal of Vacuum Science & Technology A ( IF 2.9 ) Pub Date : 2020-06-23 , DOI: 10.1116/6.0000261
Andreas Fischer 1 , Aaron Routzahn 1 , Sandy Wen 1 , Thorsten Lill 1
Affiliation  

In this work, the authors have investigated the dependence of the anisotropy level in an atomic layer etching (ALE) process of Al2O3 on form factor constraints when the ALE process involves etching in non-line-of-sight locations beneath a silicon nitride mask. In the experiments described here, thermal etching of Al2O3 without the use of any direction-inducing plasma components was explored utilizing the well characterized hydrogen fluoride/dimethyl-aluminum-chloride atomic layer etching process. The degree of anisotropy was quantified by measuring the ratio of lateral etch rate of this process in comparison to the vertical etch rate as a function of process step time inside 60 nm holes of aluminum oxide. Inside these holes, the authors determined that the horizontal etch rates slowed to an amount of 19% compared to the vertical rate when short process times were used. For process times operating in the saturation mode of the ALE process, horizontal etch rates per cycle could be sped up to 71% of the vertical rate but never reached parity with the latter. The authors propose a simple mechanism for explaining the anisotropy dependence on process step time and applied a reduced-order algorithm to model it. In this model, the authors introduced fitting parameters for surface modification depths and reaction times to match the experimentally found etch results. Conclusions could be drawn regarding topological hindrance or tortuosity for reactants to reach surfaces in shaded areas under the mask and for reaction by-products to escape from these locations and the impact on etch rate. In addition, the authors recognize that this mechanism could explain the unwanted depth dependence of the etch rate per cycle in high aspect ratio structures.

中文翻译:

纳米结构热原子层蚀刻中各向异性的原因

在这项工作中,作者研究了当ALE工艺涉及在硅下方的非视线位置进行蚀刻时,Al 2 O 3原子层蚀刻(ALE)工艺中各向异性水平对形状因子的依赖性。氮化物掩模。在此处所述的实验中,对Al 2 O 3进行热蚀刻在不使用任何诱导方向的等离子体成分的情况下,利用特征明确的氟化氢/二甲基铝-氯化物原子层刻蚀工艺进行了研究。通过测量该工艺的横向刻蚀速率与垂直刻蚀速率之比作为在60 nm氧化铝孔内的工艺步骤时间的函数,可以量化各向异性程度。在这些孔中,作者确定当使用较短的处理时间时,水平蚀刻速率比垂直蚀刻速率降低了19%。对于在ALE工艺的饱和模式下运行的工艺时间,每个周期的水平蚀刻速率可以提高到垂直速率的71%,但从未达到与后者相等的水平。作者提出了一种简单的机制来解释各向异性对工艺步骤时间的依赖性,并应用了降阶算法对其进行建模。在该模型中,作者介绍了用于表面改性深度和反应时间的拟合参数,以匹配实验发现的蚀刻结果。对于反应物到达掩模下方阴影区域的表面以及反应副产物从这些位置逸出以及对蚀刻速率的影响,可以得出有关拓扑障碍或曲折的结论。另外,作者认识到,这种机制可以解释高纵横比结构中每个周期的蚀刻速率与深度之间的不希望的关系。作者介绍了用于表面改性深度和反应时间的拟合参数,以匹配实验发现的蚀刻结果。对于反应物到达掩模下方阴影区域的表面以及反应副产物从这些位置逸出以及对蚀刻速率的影响,可以得出有关拓扑障碍或曲折的结论。此外,作者认识到,这种机制可以解释高纵横比结构中每个周期的蚀刻速率与深度之间的不想要的关系。作者介绍了用于表面改性深度和反应时间的拟合参数,以匹配实验发现的蚀刻结果。对于反应物到达掩模下方阴影区域的表面以及反应副产物从这些位置逸出以及对蚀刻速率的影响,可以得出有关拓扑障碍或曲折的结论。此外,作者认识到这种机制可以解释高纵横比结构中每个周期的蚀刻速率对深度的不希望有的依赖性。
更新日期:2020-07-09
down
wechat
bug