Characteristics of deposited Eu₂O₃ film as a thick gate dielectric for silicon

Dept. of Physics, College of Science, University of Bahrain, PO Box 32038, Bahrain

Corresponding author: adakhil@sci.uob.bh

Received: 24 June 2003
Revised: 3 March 2004
Accepted: 8 April 2004
Published online: 25 August 2004

Abstract

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 (N_ss) at the insulator/semiconductor (I/S) interface. The method of capacitance-voltage (C − V) measurements was used to determine the N_ss. 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.