Optimization of the Sputtering Process for TiN Thin Films as Electrodes in DRAM Capacitors

The metal/insulator/metal capacitor structure demands high capacitance density and effective leakage current suppression. Titanium nitride (TiN), with its suitable work function (∼4.3 eV) and exceptional thermal stability, is a widely adopted electrode material. TiN thin films deposited via Radio frequency (RF) sputtering ensure superior interface quality and device reliability due to precise compositional control, high deposition rates, and minimal contamination.In this study, TiN deposition was optimized using RF sputtering by systematically adjusting deposition parameters, including pressure, plasma power, and gas flow rate. As a result, the resistivity of TiN was successfully reduced to 140.0 μ Ωㆍcm under optimal conditions: deposition pressure of 0.3 mTorr, plasma power of 200 W, and an argon gas flow rate of 35 sccm. This optimized TiN sputtering process was applied to the bottom electrode of TiO₂-based capacitors, achieving a dielectric constant of 37 and maintaining a low leakage current, demonstrating its suitability for high-performance capacitor applications.