Defect generation and recovery in high-k HfO₂/SiO₂/Si stack fabrication

The defect generation and recovery are studied in a high-k HfO₂/SiO₂/Si stack for MOSFETs, at each fabrication step. The stack is fabricated in a well-established manner, via chemical oxidation for a SiO₂ interfacial layer and atomic layer deposition for a HfO₂ layer, followed by post-deposition annealing (PDA), O₂ plasma treatment, and forming gas annealing (FGA). Throughout the fabrication, the carrier lifetime is measured for monitoring the defects in the stack. The measurements indicate that the defects are generated by the HfO₂/SiO₂ stack formation as well as PDA and O₂ plasma treatment, whereas those defects are mostly recovered by FGA.