Influence of activated polymer on the etching rate of silicon in CF 4+H 2 plasma

Abstract

The reactive ion etching (RIE) of silicon in CF 4+H 2 plasma is considered. The influence of activated polymer on the RIE rate of silicon in CF 4+H 2 plasma is determined by extrapolation of experimentally measured kinetics of the etching rate. It is found that increased adsorption of CF 2 radicals suppresses the RIE rate of silicon in CF 4+H 2 plasma during the initial stages of the etching process. The formation of activated polymer becomes pronounced when adsorbed CF 2 radicals are slowly activated. The activated polymer intensifies the etching reaction and enhances the etching rate. C atoms, produced during the reaction, contribute to the formation of polymer on the surface. The increased concentration of the polymer suppresses the RIE rate of silicon in CF 4+H 2 plasma at later stages of the etching process.