Leakage-Induced Hot Carrier Instability in Phosphorus-Doped SiO2 Gate IGFET Devices

A reliability study has been performed on discrete n-channel IGFETs having phosphorus-doped SiO2 as a gate dielectric to characterize and determine the extent to which a new type of threshold voltage instability due to the leakage-induced hot carrier injection from the silicon substrate into SiO2 is present. A first-order trapping kinetics model with linearly varying trap centers in oxide layer is used to analyze time and temperature data of this shift. The model predicts that the shift ¿V obeys (¿V)1/2 lnt law. From the value of the activation energy that was determined, it was found that the diffusion leakage current dominates the induced threshold voltage shift. The capture cross section of the trapping centers is estimated as 2.46 × 10¿13 cm2.