Enhancement of electrical characteristics and reliability in crystallized ZrO2 gate dielectrics treated with in-situ atomic layer doping of nitrogen

The crystallized ZrO2 high-K gate dielectrics treated with in-situ atomic layer doping of nitrogen using remote N2 and NH3 plasma were investigated, to suppress the capacitance equivalent thickness (CET), leakage current density (Jg), and interfacial state density (Dit). The stress-induced leakage current (SILC) was reduced significantly as well. The tetragonal/cubic phase of ZrO2 was formed by post metallization annealing at a low temperature of 450 °C to offer a high dielectric constant of the gate oxide. The in-situ atomic layer doping of nitrogen using the remote NH3 plasma contributes to the deactivation of the oxygen vacancies and the well passivation of Dit. Accordingly, a suppressed Jg of 4.79 × 10−5 A cm−2 and Dit of 3.96 × 1011 cm−2 eV−1 were realized in the crystallized ZrO2 gate oxide with a low CET of 1.35 nm. The gate dielectrics were also optically examined by the photoluminescence from the high-K/Si interface, indicating that the Dit is highly correlated with the hydrogen passivation originating from the remote NH3 plasma. The results indicate that in-situ atomic layer doping of nitrogen is an applicable and effective technique to improve the electrical properties of crystallized gate dielectrics in the advanced metal-oxide-semiconductor devices.