使用脉冲调制射频源等离子体对纳米图案化磁隧道结叠层进行图形化刻蚀的特性研究

Etch Characteristics of Nanoscale Patterned Magnetic Tunnel Junction Stacks Using Pulse-Modulated Radio Frequency Source Plasma.

机构信息

Department of Chemistry and Chemical Engineering, Center for Design and Applications of Molecular Catalysts, Inha University, 100 Inharo, Michuhol-Gu, Incheon 22212, Korea.

出版信息

J Nanosci Nanotechnol. 2020 Aug 1;20(8):5131-5137. doi: 10.1166/jnn.2020.17804.

DOI:10.1166/jnn.2020.17804

PMID:32126711

Abstract

Magnetic tunnel junctions (MTJs) patterned with 70 × 70 nm² square arrays were etched in a CH₄/O₂/Ar gas mixture by pulse-modulated inductively coupled plasma reactive ion etching (ICPRIE). A good etch profile of MTJs with etch slope of approximately 82° was achieved by adjusting the on-off duty ratio of the plasma and pulse frequency. Langmuir probe analysis and optical emission spectroscopy confirmed that the balance between the formation of the passivation layer as an etch byproduct and sputtering effect is responsible for the etch selectivity and etch profile with a high degree of anisotropy. It is concluded that the application of pulse-modulated plasma on ICPRIE can be an effective method to obtain the anisotropic etch profile of nanometer-scale MTJs.

摘要

采用脉冲调制电感耦合等离子体反应离子刻蚀（ICPRIE）技术，在 CH₄/O₂/Ar 混合气体中对 70×70nm² 正方形阵列的磁性隧道结（MTJ）进行刻蚀。通过调整等离子体的通断比和脉冲频率，获得了具有约 82°刻蚀斜率的 MTJ 良好的刻蚀形貌。Langmuir 探针分析和光发射光谱证实，作为刻蚀副产物的钝化层的形成与溅射效应之间的平衡决定了刻蚀选择性和具有高各向异性的刻蚀形貌。研究结果表明，将脉冲调制等离子体应用于 ICPRIE 是获得纳米级 MTJ 各向异性刻蚀形貌的有效方法。