Properties of SnO2 Films Grown by Atomic Layer Deposition

In this study, we report on the influence of deposition temperature on the properties of SnO2 thin films grown by atomic layer deposition (ALD) at temperatures between 300 and 450oC with SnCl4 and H2O as the reactants. The SnO2 films were grown on silicon and glass substrates for the analysis of growth rate, crystallinity, resistivity, carrier concentration, carrier mobility, and visible light transmittance. Ellipsometry measurements showed that the growth rate of SnO2 increased with the increase of deposition temperature, but it became instable as the deposition temperature was above 450oC. Scanning electron microscope images demonstrated that the crystal shape and size changed with the deposition temperature. Four-point probe measurements indicated an increase of film resistivity with increasing the deposition temperature. Hall Effect measurements revealed that the increase of resistivity was due to the decrease of carrier concentration. UV/Vis spectrophotometry measurements indicated that the film transmittance was independent of the deposition temperature and was similar for various films with the same thickness.