Thin Eu2O3 films were prepared on Si (P) substrates to form MOS
devices. The oxide films were characterised by X-ray fluorescence (EDXRF)
and X-ray diffraction (XRD). The ac conduction mechanism and the dielectric
properties of the oxide layers were studied at room temperature and in the
temperature range of 290–420 K. We have also investigated the effect of the
oxide-crystal structure on the surface density of states (Nss) at the
insulator/semiconductor (I/S) interface. The method of capacitance-voltage
(C − V) measurements was used to determine the Nss. It was concluded that
the density of surface states in the mid-gap increases by about 30 times
when the oxide Eu2O3 crystallises in polycrystalline form. Also,
the density of the trapped charges in the oxide layer decreases by about 12
times when the oxide crystallises. The infrared studies inform us about the
humidity incorporation in the oxide film in form of chemisorbed hydroxyl
(OH) groups that leave the film for T > 373 K
