Characterisation of oxidised gadolinium film deposited on Si (1 0 0) substrate

Abstract

Thin Gd 2O 3 films were prepared by oxidation of Gd films grown on quartz and Si (P) substrates. The oxide films were characterised by X-ray fluorescence (XRF), X-ray diffraction (XRD), and optical absorption spectroscopy. The constructed Al/Gd 2O 3/Si MOS devices were characterised by measurement of gate-voltage dependence of their capacitance and ac conductance, from which the surface states density ( N ss) of insulator/semiconductor (I/S) and the density of fixed charges in the oxide were determined. The electrical conduction and dielectric properties of the Gd 2O 3–Silicon structure were studied by ac and dc methods at room temperature and in the range of 293–343 K. The data of the ac measurements follow the correlated barrier-hopping (CBH) model and the data of the dc measurements obey the trap-charge-limited space-charge-limited conduction (TCLC–SCLC) mechanism. It was noticed that the total trap concentration ( N t) deduced from dc measurements has the same order of magnitude as the concentration of localized states ( N LS) extracted from ac measurements. The infrared studies informed us about the chemisorbed hydroxyl (OH) groups incorporation in the oxide film, which leave the freshly heated-treated film at 673 K.