Conduction and field induced degradation in thin ZrO2 films sputtered in nitrogen containing plasma on silicon
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This paper deals with the electrical and stress induced degradation of reactively sputtered ZrO2/Si interface deposited in N2 containing plasma and pure argon ambient. MOS C–V and I–V techniques were used for interface characterization. Leakage current and flat band shifts were compared for ZrO2 films deposited with and without N2 containing plasma. The effect of current stress and post deposition annealing carried out on the samples deposited in different ambient was investigated. The annealed devices showed better electrical and reliability characteristics. The flat band voltage shifts towards negative value in annealed devices on being stressed, indicating positive charge trapping in the high-k dielectric layer. The flat band voltage saturates faster when stressed with higher current density. The oxide charge density increases from 4.5 × 1012 cm−2 for as deposited samples to 5.6 × 1012 cm−2 on application of stress. The samples grown in pure argon ambient showed enhanced leakage when compared with samples grown in nitrogen ambient on application of stress .
KeywordsHfO2 Flat Band Current Stress Pure Argon Ambient Capacitance Voltage
The authors would like to express their sincere thanks to Dr. M. D. Tiwari, Director and Prof. M. Radhakrishna for their constant support and encouragement.
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