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

By studying systematically the breakdown mechanisms of HfO2 and interfacial SiO2 separately in this work, we have demonstrated that defect generation in the interfacial SiO2 layer seems to be the leading breakdown mechanism in the metal/high- κ /interfacial layer/Si gate stack. The individual breakdown characteristics of HfO2, without any interfacial layer using a metal-insulator-metal capacitor, and an in situ steam-grown SiO2 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.