Reaction paths of phosphine dissociation on silicon (001)

Abstract

Using density functional theory and guided by extensive scanning tunneling microscopy (STM) image data, we formulate a detailed mechanism for the dissociation of phosphine (PH3) molecules on the Si(001) surface at room temperature. We distinguish between a main sequence of dissociation that involves PH2+H, PH+2H, and P+3H as observable intermediates, and a secondary sequence that gives rise to PH+H, P+2H, and isolated phosphorus adatoms. The latter sequence arises because PH2 fragments are surprisingly mobile on Si(001) and can diffuse away from the third hydrogen atom that makes up the PH3 stoichiometry. Our calculated activation energies describe the competition between diffusion and dissociation pathways and hence provide a comprehensive model for the numerous adsorbate species observed in STM experiments.

Dissociation of CH3–O as a Driving Force for Methoxyacetophenone Adsorption on Si(001)

“…By comparison with previous works for organic attachment to silicon we can anticipate the kinetic barriers to dative adsorption are very small and easily overcome at room temperature. 7,35,40 Of the various transitions in Fig. 3, the next smallest barrier is likely to be the H shift reaction in the initial stages of pathway 1 and likewise comparison to previous work suggests this barrier will be easily overcome at room temperature, leading us to conclude that adsorption of p-methoxyacetophenone to Si(001) may rapidly progress via dative bonding and H shift reaction to form the across-trough dative structure shown in Fig.…”

First-Principle Study of Phosphine Adsorption on Si(001)-2 × 1–Cl

“…Phosphine adsorption on clean Si(001) surface is a broadly discussed (see Ref. 6 and Refs. therein) and well-researched topic.…”

Reaction pathways of BCl$_3$ for acceptor delta-doping of silicon

“…This contrasts with earlier work with phosphine which shows a several step dissociation pathway and higher reaction barriers for full dissociation. 30 STM is also used to observe adsorbed BCl 3 -related species (BCl x with x = 1 to 3) on a Si(100) surface before and after annealing, with changes in surface structures found to be in good agreement with the dissociation behavior predicted by the model. This work further confirms BCl 3 to be an ideal acceptor precursor for APAM processes with these refinements pointing the way toward room-temperature fabrication of bipolar nanoelectronic devices, 14 acceptor based qubits, 15 and superconducting regions within Si.…”

“…Attempt frequencies are set to 10 12 s −1 as a reasonable order of magnitude estimate based on an analysis of attempt frequencies for the dissociation of PH 3 on Si. 30 We calculate the effusive flow rate of molecules landing on any particular Si dimer as…”