Co-sputtered ZnO:Si thin films as transparent conductive oxides

Silicon doped Zinc Oxide thin films, so-called SZO, were deposited at room temperature on glass and plastic substrates by co-sputtering of ZnO and SiO2 targets. The influence of the SiO2 target power supply (from 30 to 75W) on the SZO thin film composition and crystallinity is discussed. Si/Zn atomic ratio, determined by X-ray microprobe, increases from 1.2 to 8.2at.%. For Si/Zn ratio equal and lower than 3.9%, SZO (S3.9ZO) thin films exhibit the Wurzite structure with the (0 0 2) preferred orientation. Larger Si content leads to a decrease in crystallinity. With Si addition, the resistivity decreases down to 3.5×10−3Ω·cm for SZO thin film containing 3.9at.% of Si prior to an increase. The mean transmittance of S3.9ZO thin film on glass substrate approaches 80% (it is about 90% for the film itself) in the visible range (from 400 to 750nm). Co-sputtered SZO thin films are suitable candidates for large area transparent conductive oxides.