RF REACTIVE SPUTTERING OF ZINC-OXIDE FILMS ON SILICON AND SI-SIO2-TIN SUBSTRATES

The r.f. diode sputtering ZnO films using an Ar and O2 gas mixture has been studied as a function of the O2 content in the sputtering gas. ZnO films are deposited onto both elemental Si substrates and those with the configuration Si-SiO2-TiN. Non-stoichiometric ZnO films are deposited by the r.f. sputtering of a ZnO target in pure Ar gas and the film resistivity (rho = 0.1-10 OMEGA-cm) is particularly determined by the carrier concentration (n = 10(18)-10(19) cm-3). The highly ordered films with a preferential (002) orientation of their fibre grains are deposited in sputtering gas containing over 50% oxygen at a substrate temperature of 300-degrees-C. The reactively sputtered ZnO films are optically clear (transparence 80-90%) with a band gap of 3.22 eV.