Abstract: A high-efficiency, low-temperature, plasma-enhanced chemical vapor deposition (PECVD) system for growing or depositing various types of thin films on substrate surfaces, or etching such surfaces, using substrates of materials such as silicon, plastic, etc. The system uses a hollow-cathode-effect electron source with a surrounding confining electrode to create a plasma at the substrate surface to insure that the density of reactive species is both enhanced and localized at the substrate surface thus causing the rate of growth of the films, or the etch rate, to increase so that the process can take place at much lower temperatures and power levels. A particular embodiment involves the growing of hydrogenated amorphous silicon (a:Si:H), at room temperature, on silicon using a tubular reactor containing a cylindrical electrode lining the inside of the reactor walls acting as a counter electrode for an rf-powered, substrate-supporting electrode near the center of the reactor.