Characterization of hafnium oxide thin films prepared by MOCVD

Hafnium oxide thin films deposited by MOCVD were annealed in nitrogen at various temperatures. The as-deposited films and annealed films were characterized using Auger electron spectroscopy (AES), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The films were found to be slightly oxygen deficient. Angle-resolved XPS revealed oxygen to be residing in two different chemical states, that of oxygen in hafnium oxide, and possibly, a hafnium silicate. Auger depth profiling revealed nitrogen enrichment in an interfacial layer at the film-substrate interface, which could be the result of an ammonia pretreatment prior to deposition. The thickness of this interfacial layer was determined to be similar to15 A from TEM. Progressively larger grains were found from AFM measurements with increasing annealing temperature.