Dopant Precursor Adsorption into a Single-Dimer Window on Si(100): Computational Screening of Precursor-Resist Combinations

Envisioned spin-based quantum computers present the tremendous fabrication challenge of creating an atomically precise dopant array in Si. To meet this challenge, lithographic strategies have been successfully developed to incorporate a single phosphorus atom within a few-dimer window on Si(100). A growing number of dopant precursors, including acceptors for hole-based qubits and superconducting Si devices, and resists, such as halogens in place of hydrogen, are being explored to further expand the application space for atomic-precision fabrication. While recent ideas posit the use of single-dimer windows to control dopant placement, whether or not the precursor will “fit” into such a tight window has yet to be explored for new lithographic material systems. This is especially uncertain for relatively large precursors combined with relatively large resist atoms. In this study, density functional theory is used to calculate the initial adsorption configurations and adsorption pathways of common acceptor and donor precursors into a single-dimer window. Various resist atoms are used to identify which precursor-resist combinations are precluded on the basis of steric hindrances.