Electrical conductivity of copper oxide based cermets: V.V.Ivanov et al. (Krasnoyarsk State University, Krasnoyarsk, Russia.)

Abstract

Thin films of CuO and Cu2O were deposited from CuI as the copper source and O2 or N2O as the oxygen source. If O2 was used, both CuO and Cu2O were obtained. Cu2O was deposited at low O2 partial pressures (Po2 < 0.2 Torr) in a long isothermal hot wall chemical vapour deposition (CVD) reactor (T=500 °C). The CuO phase was obtained at a certain position in the CVD reactor and a sudden maximum in the deposition rate was then reached. The maximum was attributed to a change in the deposition mechanism upon the formation of CuO. When I2 was added to the reaction gas mixture, the maximum disappeared and the deposition rate increased. The formation of CuO was also investigated thermodynamically. For higher [I2]/[CuI] ratios, the CuO phase was stable, even at a low O2 pressure. Cu2O films were also deposited with N2O as the oxygen source. At 650 °C and with an excess of CuI, the deposition rate was found to be controlled by the decomposition of N2O. Above a linear gas flow velocity of 70 cm s−1, the deposition rate was constant, which indicated a surface-controlled process.