Theoretical Study of the Thermochemistry of Molecules in the Si−B−H−Cl System

Abstract

A self-consistent set of thermochemical parameters for about 100 molecules in the Si−B−H−Cl system is obtained using a combination of ab initio electronic structure calculations and empirical corrections (the BAC-MP4 method). The species include stable and radical species as well as a few transition states. Trends in calculated heats of formation, bond dissociation enthalpies, and heats of reaction for various molecular decomposition channels are discussed. Silylboranes are most likely to decompose via the elimination of H2, HCl, or silylenes. The presence of the B atom reduces the energy required for the 1,1 elimination of H2 from the Si atom, relative to the analogous reaction in disilane.

Insights into the Nature of SiH4−BH3Complex: Theoretical Investigation of New Mechanistic Pathways Involving SiH3•and BH4•Radicals

“…It is interesting to note that unlike typical hydrocarbons, wherein double or triple bonds exist, unsaturated silicon hydrides exhibit a tendency to form bridged hydrogen bonds. On a similar note, unsaturated silyboranes SiBH 1 - 5 also seem to exhibit the existence of bridged hydrogen bonds. − However, little is known about the existence of similar bridged hydrogen bonds in the interaction of saturated silicon hydrides with borane.…”

“…On a similar note, unsaturated silyboranes SiBH 1-5 also seem to exhibit the existence of bridged hydrogen bonds. [34][35][36][37][38] However, little is known about the existence of similar bridged hydrogen bonds in the interaction of saturated silicon hydrides with borane.…”

Gas Phase Reactions between SiH4and B2H6: A Theoretical Study

“…[22][23][24][25][26][27] In particular, on the observation that B 2 H 6 can raise the silicon deposition rate to a certain extent in some experiments, 28,29 various boron-silicon hydrides are investigated theoretically. [30][31][32] It is not clear, however, what kinds of initial chemical reaction are actually induced between the two sourcegas molecules SiH 4 and B 2 H 6 , and no detailed pathways have been traced to the small precursors formed from the original mixtures. In previous works, 33,34 we have demonstrated the existence of a hydrogen-bridged SiH 4 -BH 3 complex.…”

“…Clearly, the species formed from the gas phase is highly dependent on the experimental condition. As the information about the relationship between conditions and solid properties accumulates, − some theoretical mechanisms involving the gas phase and surface are also proposed. − In particular, on the observation that B 2 H 6 can raise the silicon deposition rate to a certain extent in some experiments, , various boron−silicon hydrides are investigated theoretically. − It is not clear, however, what kinds of initial chemical reaction are actually induced between the two source-gas molecules SiH 4 and B 2 H 6 , and no detailed pathways have been traced to the small precursors formed from the original mixtures. In previous works, , we have demonstrated the existence of a hydrogen-bridged SiH 4 −BH 3 complex.…”

Ab Initio Predictions for Thermochemical Parameters for Tin−Oxygen Compounds

“…The scant thermochemical data available for tin compounds containing oxygen have been determined experimentally, and we are aware of no ab initio studies of the thermochemistry of tin−oxygen compounds, although a few studies report ab initio bond energies for Sn−X bonds (X = C, Si, Ge, Sn, Pb, Cl) for various other tin-containing species. − Our laboratory at Sandia has previously made extensive use of ab initio methods to generate thermochemical data for a wide range of main-group compounds, including ones containing boron, , carbon, nitrogen, aluminum, , silicon, ,− gallium, , and indium . The methods used in these calculations are based on the bond-additivity correction (BAC) approach using fourth-order Møller−Plesset perturbation theory, in which empirically derived corrections are used to obtain accurate heats of formation .…”