Study On Highly Transparent Conductive ZnO,FZO And AZO Thin Films By Reactive Magnetron Sputtering

ZnO-based thin films,one of the most possible candidates to ITO thin films,have attracted considerable interests of researchers.Different from usually used metal or oxide target,Zn/ZnO and Zn/ZnO/ZnF2 mixtures as well as Zn/ZnO mixture with surface attached with Al strips?Al@Zn/ZnO?were used as targets in this paper.By magnetron sputtering these three targets,ZnO,F-doped ZnO?FZO?and Al-doped ZnO?AZO?thin films were prepared under atmosphere of Ar+O₂ or Ar+H₂ and substrate temperature?Ts?of 150 or 300?.The effects of Ts and reactive gas?O₂ or H₂?flux on the structure and transparent conductive properties of the films were investigated by interference microcopy,XRD,Hall effect measurement instrument and UV-Vis spectrophotometer,The results indicate thickness of three films obviously increases with O₂ flux but tends to decrease with H₂ flux.At higher Ts,the thickness of films prepared in Ar+H₂ atmosphere decreases,but that in Ar+O₂ atmosphere has not obvious change.In addition,only diffraction peaks of wurtzite structured ZnO are observed in three films although the Zn,ZnF2 and Al phases exist in the targets.Only at suitable fluxes of O₂ or H₂,the ZnO and FZO films show?002?preferred orientation,lower compressive stress and higher crystallinity,and high concentration of V0 and/or Hi defects can be formed at the same time,which results in the films with low resistivity.The films have higher transmittance at the same time,and thus the films with higher figure of merit?FOM?are obtained at suitable fluxes of O₂ or H₂.Compared with the films deposited at Ts of 150?,the films deposited at Ts of 300 ? have higher crystallinity and keep the strong?002?preferred orientation at all the O₂ or H₂ fluxes.As Ts increases,the conductive properties of the films deposited in Ar+O₂ atmosphere enhances and thus the FOM of the films improve,but conductive properties of the films deposited in Ar+H₂ atmosphere degrade,which cause the decrease in FOM of the films.As similar with Ts of 150 ?,the films keep higher crystallinity and transmittance only at suitable O₂ or H₂ fluxes when Ts is 300 ?.On the whole,the energy gap?Eg?of two films is mainly controlled by BM effect.As for AZO films,they are amorphous and have high resistivity when sputteringatmosphere is Ar+H₂,At both Ts,the films always keep strong?002?preferred orientation and conductive properties of the films trend to improve as O₂ flux increases;only O₂ flux above a certain values,the film prepared can be achieved with higher transmittance and FOM.As Ts increases from 150 to 300 ?,the film crystallinity improves but the resistivity has not obvious change.The Eg of AZO films is mainly due to their internal stress.