Structural and electrical properties of as-deposited and annealed DC sputtered ITO thin films

We have studied the effect of annealing on the structural and electrical properties of tin-doped indium oxyde, In2O3:Sn (ITO), thin films prepared by DC sputtering at different partial pressure of oxygen (ppo). Annealing experiments have been done in vacuum and in Ar atmosphere up to a temperature of 450 degrees C. A change of texture from [100] to [111] as the ppo was increased was noted in the as-deposited films. Annealing induced cristallinity and improved the texture of these films. The lattice constant decreased after annealing. The (222) grain size increased after vacuum annealing but was unaffected by annealing in Ar atmosphere; while the (400) grain size decreased for samples having the [100] texture. The electrical resistivity decreases sharply after annealing to a minimum value of 87 x 10(-4) Omega cm.