Dopant Precursor Adsorption into Single-Dimer Windows: Towards Guided Self-Assembly of Dopant Arrays on Si(100)

TL;DR

This paper explores a guided self-assembly method using molecular precursor adsorption into single-dimer windows on Si(100) to create precise dopant arrays for quantum computing, leveraging DFT calculations.

Contribution

It introduces a novel self-assembly process for dopant array fabrication on Si(100) using molecular precursors and DFT analysis of adsorption behaviors.

Findings

PH₃ adsorbs barrierlessly on all studied resists.

BCl₃ has the highest adsorption barrier of 0.34 eV.

AlCl₃ dense arrays are feasible under experimental conditions.

Abstract

Atomically precise dopant arrays in Si are being pursued for solid-state quantum computing applications. We propose a guided self-assembly process to produce atomically precise arrays of single dopant atoms in lieu of lithographic patterning. We leverage the self-assembled c(4x2) structure formed on Br- and I-Si(100) and investigate molecular precursor adsorption into the generated array of single-dimer window (SDW) adsorption sites with density functional theory (DFT). The adsorption of several technologically relevant dopant precursors (PH$_3$, BCl$_3$, AlCl$_3$, GaCl$_3$) into SDWs formed with various resists (H, Cl, Br, I) are explored to identify the effects of steric interactions. PH$_3$ adsorbed without barrier on all resists studied, while BCl$_3$ exhibited the largest adsorption barrier, 0.34 eV, with an I resist. Dense arrays of AlCl$_3$ were found to form within experimentally realizable conditions demonstrating the potential for the proposed use of guided self-assembly for atomically precise fabrication of dopant-based devices.