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), O-2 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 O-2 plasma treatment, whereas those defects are mostly recovered by FGA.