Tailoring Surface Chemistry and Morphology of Titanium Nitride Electrode for On-Chip Supercapacitors

To meet the rapidly growing demands for energy autonomous operation and miniaturization of electronic devices, it is desirable to develop high-performance ultracompact supercapacitors based on advanced thin film technology as integrated power sources. In this work, porous titanium nitride (TiN) electrode films were deposited on silicon substrate by direct current (DC) reactive sputtering. The influence of working pressure on the properties of TiN films was investigated in detail in terms of crystalline structure, composition, morphology, conductivity, and electrochemical performance. Prototype microsupercapacitors were fabricated using nano/micro-meter thick TiN electrodes prepared under optimized sputtering conditions, and superior energy as well as power densities were achieved with values as high as 23 mWh cm–3 and 7.4 W cm–3. Furthermore, the capacitance exhibits an outstanding cycling stability over 10 000 cycles. The superior energy storage performances together with excellent semiconductor process compatibility prove the porous TiN films promising for on-chip miniaturized supercapacitors.