CexAlyOz/TiN stack analysis for Metal–Insulator–Metal applications: Effect of annealing and the metal electrode deposition method

Abstract

CexAlyOz thin films were deposited on TiN metal electrode by metalorganic chemical vapour deposition method at 400°C. The detailed physical characterization on CexAlyOz/TiN stack upon annealing at different temperatures (600°C and 850°C) and for different deposition methods (Atomic vapour deposition (AVD) and Physical vapour deposition (PVD)) of electrode material were done for possible Metal–Insulator–Metal applications. X-ray diffraction results exhibited that the dielectric and TiN(AVD) are amorphous while TiN(PVD) is crystalline for the as deposited stacks. Annealing on CexAlyOz/TiN(AVD) at 600°C, initiates CeO2 crystallization in the dielectric with composition of Ce:Al=0.5 as obtained by X-ray photoelectron spectroscopy. In CexAlyOz/TiN(PVD) stack, the dielectric remains in its amorphous state until 850°C. However, TiO2 crystallization is formed at 600°C in CexAlyOz/TiN(PVD). Time of flight secondary ion mass spectroscopy depth profiling data proves that the annealing at 600°C caused the oxidation of both the metal electrodes and the inter-diffusion of Ti from the bottom metal electrode through the dielectric layer.