Preparation of rare earth CeO2 thin films using metal organic decomposition method for metal-oxide–semiconductor capacitors

Abstract

Investigation of metal organic decomposed rare earth cerium oxide thin films deposited on Si substrate by sol–gel spin coating technique was carried out. The structural properties have been examined by using XRD, Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM). The XRD confirms the cubic phase of CeO2 thin films with (111) plane observed at 28.54°. The FTIR and EDAX spectra confirm the formation of CeO2 films with atomic percentage of 19.39 and 54.82% of Ce and O2, respectively. Thickness of 60.11 nm of CeO2 film measured by cross sectional FESEM image, the average roughness of ~0.6 nm of 400 °C annealed CeO2 films were observed from AFM micrograph. The MOS capacitors were fabricated by using Ti/Au bilayer metal contact depositing by E-beam evaporator on CeO2/Si thin film for electrical measurements. Capacitance and conductance voltage measurement was carried out to determine the effective oxide charges (Qeff), interface trap density (Dit) and dielectric constant (k) and are 2.48 × 1012 cm−2, 1.26 × 1012 eV−1cm−2 and ~39, respectively. The effective metal work function of 5.68 for Ti/Au bilayer is observed to be higher than the work function of Ti or Au metals in vacuum.