Investigation and modeling of stressed thermal oxides

A comprehensive Picture of SiO2 degradation after electrical stress is proposed. starting from a kinetics model of defect creation. Two different techniques have been used to monitor changes in oxides: (1) a current-voltage technique (I-F) focused on the investigation of the stress induced leakage current in MOS capacitors, and (2) a frequency-resolved capacitance technique. The value of defect density (N) yielded by the kinetics model has been used as the input of a trap assisted tunnel (TAT) model and gave low-field current curves which fit experiments remarkably good. The same value of N has been also used in a model of differential capacitance and gave excellent fits of low-frequency capacitance data, involving tunnel in slow traps located at the silicon interface. Dependence of the low-field current and low-frequency capacitance on the stress conditions were also modeled. Therefore, the kinetics model of defect creation used in conjunction,kith TAT model at low-fields and low-frequency capacitance gives an overall comprehension of stress induced changes in thermal oxides. (C) 2002 Elsevier Science Ltd. All rights reserved.