Localized Random Telegraphic Noise Study in HfO2 dielectric stacks using Scanning Tunneling Microscopy — Analysis of process and stress-induced traps

The study of local Random Telegraphic Noise (RTN) in HfO
₂
dielectric blanket films using Scanning Tunneling Microscopy (STM) is presented in this work. Analysis of the trap spectroscopy in the dielectric by low-voltage sensing of RTN signals at different stages of stress induced leakage current (SILC) degradation and subsequent breakdown has been performed. This technique is well suited to analyze the localized progressive evolution of defects, their contribution to RTN, conduction variability and eventual failure of the high-κ dielectric. To the best of our knowledge, this is one of the first report of successful RTN sensing using STM on thin insulating films and our results indicate the potential of STM-based noise analysis for high-resolution (~10-20 nm) localized mapping of defects, which is hard to achieve at the device-level.