TiN/HfO2/SiO2/Si gate stack breakdown:: Contribution of HfO2 and interfacial SiO2 layer

By studying systematically the breakdown mechanisms of HfO(2) and interfacial SiO(2) separately in this work, we have demonstrated that defect generation in the interfacial SiO(2) layer seems to be the leading breakdown mechanism in the metal/high-kappa/interfacial layer/Si gate stack. The individual breakdown characteristics of HfO(2), without any interfacial layer using a metal-insulator-metal capacitor, and an in situ steam-grown SiO(2) metal-oxide-semiconductor capacitor with identical thicknesses and growth conditions, were compared with the gate stack characteristics. The breakdown behavior and stress-induced leakage current measurements suggest that charge trapping and stress-induced trap formation in the interfacial layer continues to be the soft spot for gate stack breakdown. (C) 2008 The Electrochemical Society.