As an emerging semiconductor optoelectronic material, Al-doped ZNO (AZO) film not only has high conductivity, high transmittance in the visible light range, but also has abundant reserves, low cost, and good stability in hydrogen plasma, and has become the preferred material to replace ITO films. In this paper, the properties of the films were characterized and analyzed by using the Qiushan Instrument Four-Probe Resistance Tester, and the effect of sputtering time on the electrical properties of the AZO films was studied.
The fixed sputtering parameters are: substrate temperature 200, target base distance 45mm, sputtering power 100W, working air pressure 03Pa, change the sputtering time to 10, 20, 30, 40, 60min, prepare azo film samples in a pure AR atmosphere, denoted as T1, T2, T3, T4, T5. The resistivity as a function of time is shown in Figure A.
The fixed sputtering parameters are: substrate temperature 400, target base distance 45mm, sputtering power 200w, working air pressure 03Pa, change the sputtering time to 10,125，15，17.5,20min, prepare azo thin film samples in a pure AR atmosphere, denoted as T6, T7, T8, T9, T10. The resistivity as a function of time is shown in Figure B.
As can be seen from Figure a, when the sputtering time is in the range of 30 min, the resistivity of the film decreases with the increase of the sputtering time, because the increase of the sputtering time will increase the thickness of the film, so that the grain size of the film increases, the degree of crystallization increases, the grain boundary scattering between grains is weakened, and the mobility of the carriers is improved, so the resistivity will decrease. When the sputtering time exceeds 30 minutes, the resistivity of the film increases and the conductivity deteriorates. Figure B has a similar trend to Figure A, except that the lowest resistivity is 148×10-4ω·cm。Comparing the A and B figures in the figure, it can also be found that the resistivity of the azo film at a substrate temperature of 400 reaches an order of magnitude of 10-3, which is much lower than the resistivity at a substrate temperature of 200, indicating that the substrate temperature has a great influence on the resistivity of the film, which is consistent with the analysis in Figure 1 (the relationship between the resistivity of the azo film and the substrate temperature).
It can be concluded that when the sputtering time is within a certain range, the resistivity of the film decreases with the increase of the sputtering time, but when the sputtering time exceeds this range, the resistivity of the film increases with time.
Specially designed for scientific research, Qiushan Instrument's four-probe resistance tester can measure the square resistance, resistivity, conductivity and other parameters of wafers up to 6 inches, and can be widely used in photovoltaics, semiconductors, alloys, conductive films and many other fields.