PBr3 Adsorption and Dissociation on the Si(100) Surface

TL;DR

This study combines STM and DFT to show that PBr3 completely dissociates on Si(100) at room temperature, enabling phosphorus incorporation into silicon for potential atomic-scale doping.

Contribution

It provides detailed experimental and theoretical insights into PBr3 dissociation on Si(100), advancing atomic-scale doping techniques.

Findings

PBr3 fully dissociates on Si(100) at room temperature.

Phosphorus atoms are incorporated into silicon after annealing.

STM images show dissociation on three neighboring Si dimers.

Abstract

The adsorption of PBr3 on the Si(100)-2$\times$1 surface was studied by scanning tunneling microscopy (STM) and density functional theory (DFT). The PBr3 molecule completely dissociates on the Si(100) surface at room temperature into P and Br atoms. In most cases, the dissociated molecule was observed in STM on three neighboring Si dimers. DFT calculations confirm that the PBr3 molecule can completely dissociate at room temperature. After annealing the sample to 400$^{\circ}$C, phosphorus is incorporated into silicon, as evidenced by the Si atoms ejected to the surface. These findings are useful for the insertion of individual phosphorus atoms into silicon by PBr3 adsorption through a halogen mask.