A recombination- and trap-assisted tunneling model for stress-induced leakage current

Charge-loss effects in device dielectric strongly limit the reliability of non-volatile memory cells. The explanation of the leakage mechanisms is the refore an essential condition for the establishment of scaled and reliable technology for data storage, This paper concerns with the physical interpre tation of the stress-induced leakage current (SILC), based on both experime ntal and computational investigations on MOS capacitor structures. It is fo und that: (a) the leakage is partly due to electron-hole recombination mech anisms in the bulk oxide, (b) defect levels acting as recombination- and tr ap-assisted tunneling (RTAT) sites are located at deep energy levels in the SiO2 and (c) the SILC characteristics of thin oxide (t(ox) < 8.5 nm) MOS s amples can be very well reproduced by a numerical model featuring RTAT as t he leading mechanism of the leakage. As a result, the oxide-degradation eff ects can be monitored by the new numerical tool. (C) 2001 Elsevier Science Ltd. All rights reserved.