发表机构
University of California, Santa Barbara; National Institute of Standards and Technology（加州大学圣塔芭芭拉分校; 美国国家标准与技术研究院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出一种基于快速热退火氧化与气相氢氟酸刻蚀的数字刻蚀工艺，将单晶硅鳍减薄至亚10纳米，为可扩展超导量子比特制造奠定基础。
AI 中文摘要
本工作提出了一种利用高电阻率浮区单晶硅晶圆实现厚度低于10纳米、高纵横比硅鳍的制造工艺。在各项异性湿法刻蚀之后，开发了一种基于重复快速热退火（RTA）氧化及对所得氧化物进行气相氢氟酸（VHF）刻蚀的数字刻蚀工艺，使得硅鳍能够减薄至亚10纳米范围。截面扫描透射电子显微镜证实了鳍厚度可薄至6纳米，尽管由于初始各向异性湿法刻蚀而呈现锥形轮廓。通过在RTA氧化过程的温度升温阶段采用N₂/O₂（5:1）气氛并降低升温速率，减少了鳍的锥度。在高度为1.2微米的鳍上，顶部厚度约12纳米、底部约15纳米，实现了沿鳍方向3纳米的厚度变化。所开发的工艺为制造约瑟夫森结提供了一条途径，为利用现成的硅处理技术实现具有单晶硅介电势垒的可重复、可扩展超导量子比特制造奠定了基础。
英文摘要
This work presents a fabrication process to realize sub-10 nm-thick, high-aspect-ratio Si fins using high-resistivity float-zone single-crystal Si wafers. Following anisotropic wet etching, a digital etching process based on repeated rapid thermal annealing (RTA) oxidation and vapor-phase hydrofluoric acid (VHF) etching of the resulting oxide was developed, enabling thinning of Si fins into the sub-10 nm regime. Cross-sectional scanning transmission electron microscopy confirms fin thicknesses as thin as 6 nm, although with a tapered profile resulting from the initial anisotropic wet etch. Tapering of the fin was reduced by using an N{_2}/O{_2} (5:1) ambient together with a reduced ramp rate during the temperature ramping for the RTA oxidation process. A thickness variation of 3 nm along a 1.2 μm tall fin was achieved on a fin with 12 nm near the top and 15 nm near the base. The developed process provides a pathway for fabricating Josephson junctions, setting a foundation toward reproducible and scalable superconducting qubit fabrication with single-crystal Si dielectric barriers using readily available Si processing technology.
