Reliability improvements of TiN/Al₂O₃/TiN for linear high voltage metal–insulator–metal capacitors using an optimized thermal treatment

Metal–insulator–metal (MIM) capacitors with TiN and high thickness of Al₂O₃ above 50 nm were fabricated to address high voltage (>30 V) and linear capacitor applications. Atomic layer deposition is used to deposit both TiN and Al₂O₃ to guarantee a good composition and thickness control. The impact of the deposition process and post-treatment condition on the MIM capacitor's breakdown voltage is studied and correlated with time of flight-secondary ion mass spectrometry (ToF-SIMS). Higher deposition temperature and thermal treatment of TiN and Al₂O₃ after deposition increase breakdown voltage and improve uniformity. ToF-SIMS demonstrates that Al₂O₃ higher deposition temperature or rapid thermal processing annealing reduce the diffusion of TiN in Al₂O₃ leading to thinner TiN/Al₂O₃ interface layers that influence breakdown voltage and uniformity.