School of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic of Korea.
Nanotechnology. 2019 Feb 22;30(8):085303. doi: 10.1088/1361-6528/aaf521. Epub 2018 Nov 30.
In this study, two Cr atomic layer etching (ALE) methods have been applied for the precise control of Cr etching. The first one involves O radical adsorption followed by Cl ion desorption (ALE with chemical ion desorption; chemical anisotropic ALE), and the second one involves Cl/O radical adsorption followed by Ar ion desorption (ALE with physical ion desorption; physical anisotropic ALE). Their effects on Cr etch characteristics were also investigated. For both the ALE methods, saturated Cr etch depth/cycle of 1.1 and 1.5 Å/cycle were obtained for the chemical and physical anisotropic ALE, respectively, while maintaining near-infinite etch selectivities with various Si-based materials like silicon, silicon dioxide, and silicon nitride. The Cr etch depth could be controlled precisely with atomic precision by controlling the etch cycles for both Cr ALE methods in addition to the infinite etch selectivities over Si-based materials. Further, the original surface roughness and chemical composition of Cr surface were maintained after Cr ALE. The ALE technique can be used to precisely control the thickness of materials, including metals such as Cr, without any surface damage.
在这项研究中，我们应用了两种铬原子层刻蚀（ALE）方法来精确控制铬的刻蚀。第一种方法涉及氧自由基吸附，随后是氯离子解吸（化学各向异性 ALE），第二种方法涉及氯/氧自由基吸附，随后是氩离子解吸（物理各向异性 ALE）。我们还研究了它们对铬刻蚀特性的影响。对于这两种 ALE 方法，化学各向异性 ALE 和物理各向异性 ALE 的饱和铬刻蚀深度/循环分别为 1.1 和 1.5 Å/循环，同时保持了与各种硅基材料（如硅、二氧化硅和氮化硅）的近无限刻蚀选择性。通过控制 Cr ALE 方法的刻蚀循环，可以精确控制 Cr 刻蚀深度，达到原子级精度，此外，Cr ALE 还具有对硅基材料的无限刻蚀选择性。此外，Cr ALE 后，Cr 表面的原始表面粗糙度和化学成分得以保持。ALE 技术可用于精确控制包括铬在内的各种材料的厚度，而不会对其表面造成任何损伤。
