Metal–insulator–metal capacitors with MOCVD grown Ce–Al–O as a dielectric

Ce–Al–O thin films were prepared on 70 nm TiN/Si(1 0 0) substrates by pulsed injection metal organic chemical vapor deposition (PI-MOCVD) for metal–insulator–metal (MIM) applications. Depositions were carried out at 400 C using two separate Ce and Al precursors. In order to get Ce–Al–O films with different stoichiometry, Al2O3 and CeO2 were mixed with different Ce:Al precursors’ ratios. According to the XRD analysis, the as deposited films were amorphous if more aluminum was injected than cerium, and crystalline – if they are cerium rich. Electrical properties have been investigated in MIM capacitors after ebeam evaporation of Au top electrodes. Oxides possess a dielectric constant of 10–20 in combination with leakage current densities as low as 10 5 A/cm at 2 V. The post deposition annealing (PDA) at 600 C and 850 C in N2 for 5 min lead to the diffusion of Ti from TiN bottom electrode and formation of the rutile TiO2 phase. Nevertheless, CeAlO3 films were obtained if the ratio of injected Ce:Al was 1:1. The k values increased to 60 in this case, but the leakage current density worsened to 10 3 A/cm at 2 V. 2011 Elsevier B.V. All rights reserved.