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O: Fachverband Oberflächenphysik

O 57: Focus Session: Semiconductor Surface Chemistry – from Reaction Mechanisms to Well-Ordered Interfaces II

O 57.1: Topical Talk

Wednesday, March 29, 2023, 15:00–15:30, GER 38

Incorporation of arsenic into silicon (001) and germanium (001) for atomic-scale device fabrication. — •Steven R. Schofield — London Centre for Nanotechnology, University College London, 17-19 Gordon St, WC1H 0AH, United Kingdom

Atomic-scale electronic devices can be fabricated via the deterministic placement of individual donor atoms in semiconductors. The commonly-used technique involves the thermal decomposition of phosphine on the Si(001) surface and the patterning of a hydrogen resist layer for spatial control. However, it is now established that the desorption of phosphorus from the surface during the thermal incorporation anneal limits the scale-up of this method, e.g., for the fabrication of large numbers of qubits. In this talk, I will present exciting new work in our group demonstrating the excellent characteristics of arsine adsorption to both Si(001) and Ge(001) for the creation of atomic-scale devices. I will present combined scanning tunnelling microscopy and density functional theory work demonstrating that arsenic incorporates into the Ge(001) surface at room temperature when exposed to arsine, thus eliminating the need for the thermal anneal that is so problematic for phosphine on Si(001). Furthermore, I will present soft x-ray angle-resolved photoelectron spectroscopy (SX-ARPES) measurements of delta-doped layers in silicon that demonstrate higher confinement for arsenic layers compared to phosphorus layers. Our new results offer exciting opportunities for the fabrication of donor-based devices and their scale-up to the large numbers of qubits required for the fabrication of technological quantum devices.