The growth process of plasma-deposited ITO films investigated by grazing incidence X-ray techniques

Thin indium tin oxide (ITO) films were deposited on Si(100) substrates by reactive d.c. magnetron sputtering from a metallic In/Sn (9/1) target. The reactive gas flow as well as negative substrate voltage were varied. The films were investigated by in situ grazing incidence X-ray diffractometry (GIXRD), grazing incidence X-ray reflectometry (GIXR), AFM and XPS. Without oxygen crystalline metallic In/Sn layers were deposited. With increasing oxygen partial pressure the amount of amorphous ITO in the layers increases. A negative substrate voltage works like a diminished oxygen flow. Using high-temperature in situ GIXRD the formation of a crystalline ITO phase due to a post-deposition heat treatment can be obtained. This ITO crystallite growth is determined by two processes, a fast crystallization process and a diffusion limited process. Depending on the deposition conditions spontaneous crystallization or diffusion dominate the crystal growth and a different sample morphology occurs. (C) 2000 Elsevier Science B.V. All rights reserved.