Diffusion and crystal growth in plasma deposited thin ITO films

Tin-doped indium oxide (ITO) films were deposited by means of DC-planar mag netron sputtering. A metallic In/Sn (90/10) target and an Ar/O-2 gas mixtur e were used. The oxygen flow was varied between 0 and 2 seem. Substrate vol tages between 0 and -100 V were used. With increasing oxygen how him struct ure and composition change from crystalline metallic In/Sn to amorphous ITO . Simultaneously the deposition rate decreases and the film density increas es. The diffusion of oxygen into metallic In/Sn films and the amorphous-to- crystalline transformation of ITO were studied using in situ grazing incide nce X-ray diffractometry (GIXRD), grazing incidence reflectometry (GIXR), a nd AFM. From the X-ray integral intensities diffusion constants, activation energies of the diffusion, reaction order and activation energy of the cry stal growth process were extracted.