Diamond deposition using a novel microwave applicator

This paper describes a novel microwave applicator that has the potential to allow microwave deposition of diamond films inside a metallic cylinder wit h an internal diameter of more than 10 cm. The design consists of a coaxial antenna that passes perpendicularly throug h a rectangular waveguide and forms a plasma inside a vacuum chamber. A qua rtz envelope around the antenna feeds reactant gases along its axis to the antenna opening. Here, the microwave field (2.45 GHz) is generated in the r eactant gasses, and a plasma jet is formed. The antenna and quartz housing are so arranged that the plasma jet emerges perpendicular to the antenna ax is. This allows the jet to be directed towards the internal surface of a cy linder with diameter > 50 mm. Diamond films have growth rates of up to 0.2-1 mu m/h and exhibit a sharp R aman peak at 1332 cm(-1). Film growth is examined under a range of conditio ns including applicator-substrate distance! microwave power, surface temper ature and chamber pressure. (C) 2000 Elsevier Science S.A. All rights reser ved.