Diamond deposition using a novel microwave applicator

This paper describes a novel microwave applicator that has been used to dep osit diamond films from a hydrogen/methane/oxygen mixture onto silicon subs trates. The design consists of a coaxial antenna that passes perpendicularl y through a rectangular waveguide and forms a plasma inside a vacuum chambe r. A quartz envelope around the antenna feeds reactant gases along its axis to the antenna opening. Here the microwave field (2.35 GHz) is generated i n the reactant gases and a plasma jet is formed. As the plasma is in the fo rm of a jet, irregularly shaped objects may be coated in the plasma without disturbing the microwave field to the extent observed in resonant held sys tems. Diamond films have growth rates of up to 0.5 mu m/h and exhibit a Ram an peak (excitation sourer HeNe laser at 632 nm) at 1332 cm(-1). Film growt h is examined under a range of conditions including applicator-substrate di stance, microwave power and chamber pressure. (C) 2000 Elsevier Science S.A . All rights reserved.