Structural and Electrical Characterization of Lu2O3 Dielectric Layer for High Performance Analog Metal–Insulator–Metal Capacitors

Abstract

The structural and electrical properties of Lu2O3 dielectric films deposited by radio frequency (RF) magnetron sputtering on TaN electrode have been studied for metal–insulator–metal (MIM) capacitor in analog/RF applications. From X-ray diffraction study, it is observed that the deposited films remain amorphous within the thermal budget (400°C) of back-end-of-line process. The root mean square value of surface roughness of the Lu2O3 film decreases after annealing at 400°C using atomic force microscopy. The chemical composition of the Lu2O3 film was characterized by X-ray photoelectron spectroscopy. The MIM capacitor using a Lu2O3 dielectric film exhibited better electrical characteristics, such as a low leakage current of 5 × 10−8 A/cm2 at −1 V and a high capacitance density of 7.5 fF/μm2 with a low quadratic voltage coefficient of capacitance of 75 ppm/V2. The current conduction mechanism was found to be dominated by Schottky emission mechanism in low electric field (<1 MV/cm) region and hence further improvement in the leakage characteristics can be realized by employing a high work-function electrode or a large bandgap oxide as a barrier layer.