Hydrogen plasma reduction of supported metal salts

Abstract

During the last thirty years, in the electronics industry, there has been increasing interest in the use of partially ionised plasmas for the processing of surfaces. A large amount of work has been carried out on plasma etching using halogen plasmas. However, halogen plasmas cause both environmental and handling problems and as a result hydrogen plasmas are often used as a substitute. Gold films are very important in the electronics industry. Several techniques have been proposed for the deposition of conducting gold films, including CVD, PVD, and Sol-gel techniques. In the work outlined in this thesis, a hydrogen plasma was generated at 0.1 torr using an RF power supply, in order to modify the surfaces of gold (III) chloride films, spin coated onto either a glass or nylon substrate. It has been postulated that if hydrogen atoms will react with a material in a plasma to form a volatile compound (eg. HCl), then the surface will be modified. The aim of this work was to create a conducting gold film, by removal of chlorine species from the original spin coated film, through use of a hydrogen plasma. The results of this work demonstrate that chlorine removal from the original film, by use of a hydrogen plasma, is a function of the concentration of the spin coated AuCl(_3); the plasma treatment time; and the plasma power. The substrate onto which the AuCl(_3) is deposited also appears to play an important role. The deposition method proposed in this thesis is a quick, cheap and easy way to deposit thin gold films.