EAGER: Quantum Manufacturing: Robust Atom-based Silicon Quantum Devices

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This EArly-concept Grant for Exploratory Research (EAGER) Quantum Manufacturing award supports research to expand manufacturing processes for semiconductor electronic and quantum devices by advancing the science needed to manufacture devices down to the size-scale approaching single atoms. The results of this research will enable manufacturing of semiconductor devices at size scales not possible today, advancing national prosperity and security. A scanning tunneling microscope is used as a fabrication tool to deterministically place individual phosphorus dopant atoms in silicon with near lattice site perfection. Atomic-scale gates and leads for few atom transistors, dopant-based few-atom qubit devices and dopant arrays for analog quantum simulation can now be fabricated for scientific experiments. The exact positions of dopants play an essential role in device performance, driving the need for atomic perfection. Current imprecision in dopant concentration or dopant position still prevents robust manufacturing. Atom-based silicon quantum devices have generated excitement because they promise to provide the smallest, most dense quantum devices while still leveraging the power of traditional silicon electronics. Robust atom-based silicon quantum devices require advanced manufacturing with precise control over the number and precision of dopant placement. The work here will push traditional nanoscale manufacturing science toward robust atom-scale manufacturing where silicon-based devices can be routinely fabricated atom-by-atom. The research will accelerate manufacturing into the realm of atom-scale devices. Developing robust manufacturing of atom-scale solid state quantum devices will help address the critical national need for successful quantum platforms that can be integrated with conventional electronics.Feedback-controlled lithography was developed to allow atom-scale perfect placement of an individual phosphorus (P) dopant on silicon (Si). This research will advance from one-time demonstrations of perfect placement to robust precise placement of individual atoms that can be used to manufacture atom-scale solid-state Si devices. Perfect placement will be extended to acceptors like boron (B). This additional capability will provide a wider class of quantum devices that can be manufactured and exploited. Density functional theory will be used to simulate scanning tunneling images and determine preferred adsites for B2H6 and its breakdown species. A similar catalog of images will be generated for two-donor and two-acceptor structures. The catalogs will be used to identify deposited structures and new feedback control will be developed to ensure precise placement of B acceptors and multi-dopant structures. Transport and related experiments on these devices will be performed and compared to theory to verify the precision fabrication of atom geometries as designed.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.