EPMA and ellipsometric characterization of PECVD boron-carbon films

Abstract
The characteristics of a-B/C : H films, produced by PECVD on Si (100) surface using the novel harmless precursorcarborane have been studied. These films proved to be excellent for protection tokamaks inner surfaces, for they are heat-proof and chemically resistant. EPMA and ellipsometry used together enabled to determine not only the films composition and thickness, but also the density and some other parameters. A special computer program based on Yakovitz-Newbury method has been developed to study rather thin ([MATH]100nm) films by EPMA. Spectroellipsometry was used to determine the wave dependence of the films optical constants. It has been established that B/C ratio grows from 1 to 3.6 with increasing in carborane pressure and does not depend on a substrate temperature and voltage applied. EPMA measurements performed in cooperation with ellipsometry showed the increasing microporosity (up to 40%) for the film exposed to the fluence of deuterium ions about 10²¹cm^-2.