Radiation Induced Charge Trapping in Sputtered ${\rm ZrO}_{\rm 2} !! : !! {\rm N}$ Dielectric Thin Films on Silicon

The present paper deals with radiation induced charge trapping at reactively sputtered ZrO₂/Si interface deposited in N₂ containing plasma. MOS C-V and I-V techniques were used for interface characterization. Radiation induced degradation of sputtered high k dielectric (ZrO₂)/Si interface was studied using Cu X-ray source. The devices were irradiated with x-rays at different doses ranging from 100 rad to 1 Mrad. Enhanced leakage current and shift in flat band voltage towards negative value was observed in annealed devices after exposure to radiation. The effect of post deposition annealing on the electrical behavior of ZrO₂/Si interface was also investigated. The annealed devices showed better electrical and reliability characteristics. Different device parameters such as flat band voltage, leakage current, charge defects has been extracted. Nitrogen incorporated ZrO₂ is found to improve the radiation hardness of the devices.