Long-term stability of electrical and electrochemical properties of TiN film in the atmosphere environment

Golden-yellow, dense, and highly conductive TiN films are widely used as gate electrodes and diffusion barrier layers in microelectronics. Dark color and porous TiN films are used as electrode material for on-chip microsupercapacitors (MSCs) and nano-pore gene sequencing chips owing to their high specific capacitance. However, oxidation can lead to varying degrees of degradation in electrical and electrochemical performance, which poses long-term stability issues. To date, experimental studies on the oxidation and performance degradation of TiN films over time remain limited. This study tested the electrical conductivity, stress levels, energy storage characteristics, and room temperature oxidation performance of the newly deposited TiN film. The results indicate that the electrical conductivity and specific capacitance of TiN films can be finely tuned by controlling the working pressure. Subsequently, the electrical and electrochemical performance of the films was periodically monitored over three months, with examinations of changes in chemical composition and internal stress. The results reveal a clear pore size-related, time-dependent oxidation and performance degradation behavior, which is crucial for assessing the stability of TiN electrode films in various device applications.