Development of Crystal Growth Simulator Based on Tight-Binding Quantum Chemical Molecular Dynamics Method and Its Application to Silicon Chemical Vapor Deposition Processes

Abstract

We have developed a crystal growth simulator based on tight-binding quantum chemical molecular dynamics (TB-QCMD) method and applied it to plasma-enhanced chemical vapor deposition (PECVD) processes for silicon thin-film growth via SiH 3 radicals on hydrogen-terminated Si(001). We successfully simulated the abstraction of a surface hydrogen atom by irradiated SiH 3 radical and the formation of a dangling bond on the hydrogen-terminated Si(001) surface. SiH 3 radical was subsequently adsorbed on this dangling bond. When these processes were repeated, the thin film grew. Thus, a detailed mechanism was successfully found for the chemical reaction and electron transfer dynamics of silicon thin film growth by PECVD.

CVD precursors for transition metal oxide nanostructures: molecular properties, surface behavior and temperature effects

“…Moreover, knowledge of precursor molecular properties is a crucial step to understand how they interact with the growth surface, as well as with other gaseous species, under the CVD operating conditions . In this context, modeling approaches are playing an increasingly important role, but further progress is needed in order to gain fundamental knowledge of the basic chemistry of CVD processes .…”

The reason why thin-film silicon grows layer by layer in plasma-enhanced chemical vapor deposition

“…Long-distance diffusion of weakly physisorbed SiH 3 radicals is therefore unlikely. We also found from tight-binding quantum chemical MD simulations that the initial growth of thin-film Si follows an “abstraction-adsorption” mechanism 21 22 , where a DB is generated on the surface via H abstraction by a SiH 3 radical and the next SiH 3 radical is adsorbed onto the generated DB. Thus, although experimental results have found a relationship between surface diffusion and layer-by-layer growth 23 24 , the diffusion mechanism of SiH 3 radicals has not yet been confirmed, and the previously proposed diffusion mechanisms thus remain controversial.…”

Opening the Pandora's jar of molecule-to-material conversion in chemical vapor deposition: Insights from theory

“…Owing to its lower computational cost with respect to FPMD (about 5000 fold faster), TBMD can be applied when larger model systems and longer time scales need to be considered. This is the case of a recent TBMD simulation study of Si thin film deposition by PE‐CVD, modeling precursor adsorption/product desorption on/from the growth surface . When the plasma‐activated precursors (SiH 3 radicals) reached the substrate (a hydrogen‐terminated Si(001) surface model), processes such as hydrogen abstraction from the surface, SiH 3 adsorption on unsaturated Si atoms as well as electron injection to the surface were observed.…”

“…Up to now, examples related to the surface behavior of small, already activated precursors and of a coordinatively insaturated transition‐metal precursor have been considered. In both cases, the structure of the precursor molecule allows Si or Cu to directly interact, and finally bind, with surface atoms.…”