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Multi-scale alignment to buried atom-scale devices using Kelvin probe force microscopy



Pradeep Namboodiri, Jonathan Wyrick, Gheorghe Stan, Xiqiao Wang, Fan Fei, Ranjit Kashid, Scott Schmucker, Richard Kasica, Bryan Barnes, Michael Stewart, Richard M. Silver


Fabrication of quantum devices by atomic scale patterning with a Scanning Tunneling Microscope (STM) has led to the development of single/few atom transistors, few-donor/quantum dot devices for spin manipulation and arrayed few-donor devices for analog quantum simulation. We have developed atomic precision lithography, dopant incorporation, device encapsulation, ex situ device relocation, and contact processes to enable high yield device fabrication. In this work we describe a multiscale alignment strategy using Kelvin Probe Force Microscopy (KPFM) to enable alignment of buried device components to electronic support structures such as, source drain leads, in-plane and top gates, and coplanar waveguides while preserving the flexibility in the placement of the STM patterns. The required spatial accuracy to bridge the sub-micrometer scale central region of the device to millimeter scale large wire-bond pads is achieved through a multi-step alignment process at various stages of fabrication, including atom-scale device fabrication using STM, relocation and registration, and electron beam lithography for contact leads and pads. Central to this alignment strategy is that the KPFM can image small device regions as well as the large-scale fiducial marks, thereby bridging the gap from nanometer STM to the millimeter scale electrical contact fabrication.
Nanotechnology Reviews


Atomic Scale Devices, Kelvin Probe, Atomic Force Microscopy


Namboodiri, P. , Wyrick, J. , Stan, G. , Wang, X. , Fei, F. , Kashid, R. , Schmucker, S. , Kasica, R. , Barnes, B. , Stewart, M. and Silver, R. (2024), Multi-scale alignment to buried atom-scale devices using Kelvin probe force microscopy, Nanotechnology Reviews, [online],, (Accessed April 19, 2024)
Created February 24, 2024, Updated February 29, 2024