Non-destructive X-ray imaging of patterned delta-layer devices in silicon

Autor: D'Anna, Nicolò, Sanchez, Dario Ferreira, Matmon, Guy, Bragg, Jamie, Constantinou, Procopios C., Stock, Taylor J. Z., Fearn, Sarah, Schofield, Steven R., Curson, Neil J., Bartkowiak, Marek, Soh, Y., Grolimund, Daniel, Gerber, Simon, Aeppli, Gabriel
Rok vydání: 2022
Předmět:
Zdroj: Adv. Electron. Mater. 2023, 2201212
Druh dokumentu: Working Paper
DOI: 10.1002/aelm.202201212
Popis: The progress of miniaturisation in integrated electronics has led to atomic and nanometre-sized dopant devices in silicon. Such structures can be fabricated routinely by hydrogen resist lithography, using various dopants such as phosphorous and arsenic. However, the ability to non-destructively obtain atomic-species-specific images of the final structure, which would be an indispensable tool for building more complex nano-scale devices, such as quantum co-processors, remains an unresolved challenge. Here we exploit X-ray fluorescence to create an element-specific image of As dopants in silicon, with dopant densities in absolute units and a resolution limited by the beam focal size (here $\sim1~\mu$m), without affecting the device's low temperature electronic properties. The As densities provided by the X-ray data are compared to those derived from Hall effect measurements as well as the standard non-repeatable, scanning tunnelling microscopy and secondary ion mass spectroscopy, techniques. Before and after the X-ray experiments, we also measured the magneto-conductance, dominated by weak localisation, a quantum interference effect extremely sensitive to sample dimensions and disorder. Notwithstanding the $1.5\times10^{10}$ Sv ($1.5\times10^{16}$ Rad/cm$^{-2}$) exposure of the device to X-rays, all transport data were unchanged to within experimental errors, corresponding to upper bounds of 0.2 Angstroms for the radiation-induced motion of the typical As atom and 3$\%$ for the loss of activated, carrier-contributing dopants. With next generation synchrotron radiation sources and more advanced optics, we foresee that it will be possible to obtain X-ray images of single dopant atoms within resolved radii of 5 nm.
Databáze: arXiv