Effect of Hydrogen Coverage on Silicon Thin Film Growth: Molecular Dynamics Investigation

Abstract

AbstractSilicon thin films grown by CVD processes take various structures depending on the reaction conditions. In the case of low-temperature CVD, hydrogen coverage on the silicon substrate affects the growth as well. In order to analyze the effect of hydrogen coverage on elementary surface reactions, we performed molecular dynamics simulations in which gasphase radicals, H and SiH3, fell onto a hydrogen-terminated silicon surface. We prepared monohydride and dihydride Si(100) surfaces and modified their hydrogen coverage in a certain area in the range from 0.5 to 2.0 monolayers so as to describe the growing surface. As a result of our simulation, H radicals mainly caused H adsorption and H abstraction reactions and altered the hydrogen coverage of the surface. While reactions of SiH3 radicals with monohydride or dihydride surfaces rarely occurred, these radicals reacted more frequently with the modified surfaces. These results indicate that the change in the local hydrogen coverage caused by H radicals may induce subsequent surface reactions