Élaboration et caractérisation physique des films oxydes ITO, ZnO et ZnO : Al

Abstract

In this work, we studied the physical properties of oxide films: ITO, ZnO/glass, AZO/glass and AZO/Si prepared at different thicknesses. ITO thin films were deposited onto Si substrate (100) by RF sputtering for thicknesses ranging from 61 to 768 nm. These films are polycrystalline with the <100> texture, and are characterized by a compressive stress which decreases with increasing e. SEM and AFM images show a smooth surface with grainsb of pyramidal shape and a roughness RMS increases as e increases. the electrical resistivity ρ and the mobility μ of these films increase when e increases, while the concentration n decreases. Annealing in air at T = 400 ° C for 60 minutes improves the structural properties and gives films with larger roughness. It leads to a decrease of ρ and μ, where the lowest value of ρ is equal to 5,52x10-4 Ω.cm and to an increase of n. ZnO/glass, ZnO:Al/glass and ZnO:Al/Si(111) films were deposited by sol gel method using the dip-coating technique at different thicknesses (523 nm to 1180 nm). The films are polycrystalline with a preferred orientation in general along the c axis. The undoped ZnO films have a compact, dense and granular surface, a good transmission and a resistivity in order of 10+2 Ω.cm. Doping with Al (1.5%) leads to less rough films with a strong improvement in optical and electrical properties. The deposition of AZO films on silicon (111) present a polycrystalline structure with a higher intensity of the plane (002) and generally higher RMS roughness. The films deposited on Si are more resistive with a lower concentration n. The electrical resistivity of these films decreases when t increases from 523 à 1042nm and the lowest value is found for the 1042nm thick sample