Nucleation on SiO2 during the selective chemical vapor deposition of tungsten by the hydrogen reduction of tungsten hexafluoride

Article abstract of DOI:10.1149/1.2059366

A horizontal hot-wall chemical vapor deposition (CVD) quartz reactor with rectangular cross section was used to study the effect of different process conditions on the nucleation of tungsten on SiO₂ during selective WCVD by the H₂ reduction of WF₆. The experimental procedure included placing a metallic surface at the center of the reactor, and small samples of SiO₂ at different positions both upstream and downstream with respect to the metallic surface. Digitized scanning electron microscopy micrographs were used to determine the particle size distributions of nuclei on the SiO₂ surfaces. We found that the amount of nucleation on SiO₂ decreases when smaller metallic surfaces are present and for lower temperatures and shorter process times. Although nucleation was always greatest on SiO₂ samples closest to the metal sample, the effect of flow rate depended on the position of the SiO₂. A statistical nearest neighbor analysis indicated a clustering of W nuclei on the SiO₂. A simplified mathematical model was developed to predict concentration profiles of a gaseous intermediate generated at the metal surface during the thermal decomposition of the source gas. This intermediate has been proposed as being the reactive species that causes nucleation on SiO₂ surface. Qualitative agreement between experimental and theoretical results reinforce the proposed role of the intermediate with this species being characterized by a short lifetime.

Full text of DOI:10.1149/1.2059366

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).

Downloaded on 2015-03-29 to IP 141.217.58.200 address. Redistribution subject to ECS terms of use (see ecsdl.org/site/terms_use) unless CC License in place (see abstract).