Improved electrical characteristics and reliability of amorphous InGaZnO metal-insulator-semiconductor capacitor with high κ HfO_xN_y gate dielectric

摘要

High κ HfO_xN_y film was deposited on amorphous InGaZnO (a-IGZO) by radio-frequency reactive sputtering using an HfO_2 target in nitrogen plus argon ambience, the electrical characteristics and reliability of a-IGZO metal-insulator-semiconductor (MIS) capacitors were investigated. Experimental results indicate that the nitrogen incorporation into HfO_2 can produce a strong nitride interfacial barrier layer, thus lead to reducing the interface state density, suppressing the hysteresis voltage, and decreasing the gate-leakage current. Improved performance has been achieved for HfO_xN_y gate dielectric a-IGZO MIS capacitors, with a interface state density of 5.1 × 10~(11) eV~(-1) cm~(-2), a gate-leakage current density of 3.9 × 10~(-5) A/cm~2 at V_(fb) + 1 V, an equivalent permittivity of 24, and a hysteresis voltage of 105 mV. Moreover, the enhanced reliability of Al/HfO_xN_y/a-IGZO MIS capacitor is observed with a small degradation of electrical characteristics after a high field stressing at 10 MV/cm for 3600 s.