Power-Law Dependence of Charge Trapping on Injected Charge in Very Thin SiO2 Films

In this letter, we report a novel approach to quantitative determination of charge trapping in gate oxide caused by high field stress. Our approach is to analyze the small but significant change in the post-stress FN tunneling current through the oxide layer based on the assumption that the change in the tunneling current is due to the changes of both the oxide field and the oxide barrier heights caused by charge trapping in the oxide and at the interfaces. It is found that, regardless of injection directions and measurement polarities, the charge trapping always follows a power law of the form Q inj n with n ≈0.1 to 0.4, where Q inj is the injected charge dose.