Nondestructive imaging of atomically thin nanostructures buried in silicon.
Nondestructive imaging of atomically thin nanostructures buried in silicon.
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DOI：
10.1126/sciadv.1602586
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发表时间：
2017-06
期刊：
影响因子：
13.6
通讯作者：
Curson NJ
中科院分区：
文献类型：
--
作者：
Gramse G;Kölker A;Lim T;Stock TJZ;Solanki H;Schofield SR;Brinciotti E;Aeppli G;Kienberger F;Curson NJ
微波显微镜能够以纳米精度对原子薄半导体结构进行三维表征。现在可以在硅中创建原子级薄的掺杂剂原子区域，其横向尺寸范围从原子尺度（埃）到微米。这些结构是用于物理研究的量子设备的构建块，它们也可能作为下一代经典和量子信息处理设备的关键组件。到目前为止，埋入式掺杂剂纳米结构的特性只能通过破坏性技术和/或最终电子器件的性能来推断。这严重限制了基于原子级光刻的现实设备的工程和制造。在这里，我们使用扫描微波显微镜（SMM）对通过扫描隧道显微镜光刻制造的三维磷纳米结构进行成像和电子表征。 SMM 测量是完全无损的，并且对硅表面以下 4 至 15 nm 处的 1900 至 4200 个密集排列的 P 原子敏感，产生的电学和几何特性与从包含约 1013 个 P 原子的无图案磷 δ 层的电传输和二次离子质谱获得的结果一致。成像分辨率横向为 37 ± 1 nm，垂直方向为 4 ± 1 nm，这两个值均取决于 SMM 尖端尺寸和掺杂层深度。此外，有限元建模表明，使用进一步优化的尖端和微波梯度检测可以显着提高分辨率。我们对三维掺杂剂结构的研究结果揭示了浅掺杂剂层的载流子迁移率降低，并表明 SMM 可以帮助表面码量子计算机制造工艺的开发。
Microwave microscopy enables three-dimensional characterization of atomically thin semiconductor structures with nanometer precision. It is now possible to create atomically thin regions of dopant atoms in silicon patterned with lateral dimensions ranging from the atomic scale (angstroms) to micrometers. These structures are building blocks of quantum devices for physics research and they are likely also to serve as key components of devices for next-generation classical and quantum information processing. Until now, the characteristics of buried dopant nanostructures could only be inferred from destructive techniques and/or the performance of the final electronic device; this severely limits engineering and manufacture of real-world devices based on atomic-scale lithography. Here, we use scanning microwave microscopy (SMM) to image and electronically characterize three-dimensional phosphorus nanostructures fabricated via scanning tunneling microscope–based lithography. The SMM measurements, which are completely nondestructive and sensitive to as few as 1900 to 4200 densely packed P atoms 4 to 15 nm below a silicon surface, yield electrical and geometric properties in agreement with those obtained from electrical transport and secondary ion mass spectroscopy for unpatterned phosphorus δ layers containing ~1013 P atoms. The imaging resolution was 37 ± 1 nm in lateral and 4 ± 1 nm in vertical directions, both values depending on SMM tip size and depth of dopant layers. In addition, finite element modeling indicates that resolution can be substantially improved using further optimized tips and microwave gradient detection. Our results on three-dimensional dopant structures reveal reduced carrier mobility for shallow dopant layers and suggest that SMM could aid the development of fabrication processes for surface code quantum computers.