Correlation Between Development of Leakage Current and Hydrogen Ionization in Ultrathin Silicon Dioxide Layers

Abstract

ABSTRACTThe generation of leakage current across 3-6-nm thick thermal oxides on (100)Si under electrical stress or irradiation with 10-eV photons is compared with the radiation-induced defect generation in 35-66-nm thick SiO2 layers. The degradation of both ultrathin and conventional oxides appears correlated with the concentration of atomic hydrogen in the layer. Both the leakage currents and the irradiation-induced defects were found to have two components: one thermally unstable that correlates with the H-induced donor states, and another related to the permanent oxide network damage ascribed to H-assisted Si-O bond break. As both degradation processes involve a proton formed in the oxide, we suggest that H ionization either by electron emission or by trapping a hole triggers oxide degradation.