Gramse, G;
Kölker, A;
Lim, T;
Stock, TJZ;
Solanki, H;
Schofield, SR;
Brinciotti, E;
... Curson, NJ; + view all
(2017)
Nondestructive imaging of atomically thin nanostructures buried in silicon.
Science Advances
, 3
(6)
e1602586-e1602586.
10.1126/sciadv.1602586.
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Abstract
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.
| Type: | Article |
|---|---|
| Title: | Nondestructive imaging of atomically thin nanostructures buried in silicon |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1126/sciadv.1602586 |
| Publisher version: | http://dx.doi.org/10.1126/sciadv.1602586 |
| Language: | English |
| Additional information: | Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). |
| Keywords: | Microwave microscopy, subsurface imaging, 2D materials, dopant nanostructures, Silicon, dopant profiling, STM lithography |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1566565 |
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