HIGH-k GATE DIELECTRIC: AMORPHOUS Ta/La₂O₃ FILMS GROWN ON Si AT LOW PRESSURE

Abstract

In the present study, Ta/La 2 O 3¯l ms (La 2 O 3 doped with Ta 2 O 5 Þ as a gate dielectric were prepared using a sol-gel method at low pressure. Ta/La 2 O 3¯l m has some hopeful properties as a gate dielectric of logic device. The structure and morphology of Ta/La 2 O 3¯l ms were studied using X-ray di®raction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electrical properties of¯lms were performed using capacitance-voltage (C-V Þ and current density-voltage (J-V Þ measurements. The optical bandgap of samples was studied by UV-visible optical absorbance measurement. The optical bandgap, E opt , is determined from the absorbance spectra. The obtained results show that Ta/La 2 O 3¯l m as a good gate dielectric has amorphous structure, good thermal stability, high dielectric constant ð% 25Þ, low leakage current and wide bandgap ð% 4:7 eVÞ.