Enhancement of electrical characteristics and reliability in crystallized ZrO ₂ gate dielectrics treated with in-situ atomic layer doping of nitrogen

The crystallized ZrO ₂ high-K gate dielectrics treated with in-situ atomic layer doping of nitrogen using remote N ₂ and NH ₃ plasma were investigated, to suppress the capacitance equivalent thickness (CET), leakage current density (J _g ), and interfacial state density (D _it ). The stress-induced leakage current (SILC) was reduced significantly as well. The tetragonal/cubic phase of ZrO ₂ 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 NH ₃ plasma contributes to the deactivation of the oxygen vacancies and the well passivation of D _it . Accordingly, a suppressed J _g of 4.79 × 10 ^-5 A cm ^-2 and D _it of 3.96 × 10 ¹¹ cm ^-2 eV ^-1 were realized in the crystallized ZrO ₂ 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 D _it is highly correlated with the hydrogen passivation originating from the remote NH ₃ 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.