562015-03-24 , 法政大学大学院理工学・工学研究科
Aluminum doped zinc oxide (AZO) films (350 nm in thickness) were prepared on glass substrates by RF magnetron sputtering with a ZnO target containing 2 wt.% of Al2O3in pure Ar at 0.1 Pa. The continuous in-situ resistivity measurement was carried out by the four-point probes set in a tube furnace at the temperature range between RT and 500 ˚C in O2and N2.The Hall effect measurement was carried out by means of the Van der Pauw configuration at RT after annealing at the temperature range between 100 and 500 ˚C in O2 and N2. Structure of deposited films was examined by X-ray diffractometer (XRD) and Transmission Electron Microscope (TEM) observation. Since the X-ray diffraction profiles and the TEM images revealed that these as-deposited films were poly-crystalline and their crystal grains did not essentially grow even after annealing up to 500 ˚C, the resistivity was mainly governed by the change of the density of the oxygen vacancy emitting free electrons above 300 ˚C to 500 ˚C. For the oxidizing (O2)atmosphere annealing, the resistivity increased by the oxygen vacancy extinction above 300 ˚C to 500 ˚C while for the non-oxidizing(N2)atmosphere annealing, where extinction did not occur, the resistivity continued to decrease.