Prospects for Thermal Atomic Layer Etching Using Sequential, Self-Limiting Fluorination and Ligand-Exchange Reactions

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• 作者：Steven M. George ; Younghee Lee
• 刊名：ACS Nano
• 出版年：2016
• 出版时间：May 24, 2016
• 年：2016
• 卷：10
• 期：5
• 页码：4889-4894
• 全文大小：297K
• 年卷期：0
• ISSN：1936-086X

文摘

Thermal atomic layer etching (ALE) of Al₂O₃ and HfO₂ using sequential, self-limiting fluorination and ligand-exchange reactions was recently demonstrated using HF and tin acetylacetonate (Sn(acac)₂) as the reactants. This new thermal pathway for ALE represents the reverse of atomic layer deposition (ALD) and should lead to isotropic etching. Atomic layer deposition and ALE can together define the atomic layer growth and removal steps required for advanced semiconductor fabrication. The thermal ALE of many materials should be possible using fluorination and ligand-exchange reactions. The chemical details of ligand-exchange can lead to selective ALE between various materials. Thermal ALE could produce conformal etching in high-aspect-ratio structures. Thermal ALE could also yield ultrasmooth thin films based on deposit/etch-back methods. Enhancement of ALE rates and possible anisotropic ALE could be achieved using radicals or ions together with thermal ALE.