Abstract: Disclosed is a vapor deposition reactor comprising a series of individual gas cells respectively isolated from each other and containing a particular reactive or non-reactive gas required for one stage in a deposition process. Each cell is provided with an independent temperature control. A substrate is mounted on a carrier and transported through the series of individual cells so that vapor depositions or other related processes may be conducted or performed upon the substrate. Chemical vapor deposition processes such as growth of epitaxial layer, deposition of polycrystalline silicon, nitride, oxide or metals on a substrate may be performed within the reactor. The cells are isolated by viscous loss seals formed by the propinquity of restricted openings in the reactor to substrate carrier configuration.