Atomistic Origin of RTN-like Centers Created and Annihilated by RRAM Write Processes

Area of Science:

• Materials Science
• Solid State Physics
• Electrical Engineering

Background:

• Resistive random-access memory (ReRAM) is a promising non-volatile memory technology.
• Understanding noise mechanisms like random-telegraph-like noise (RTN) is crucial for ReRAM reliability.
• Programming pulses in ReRAM can induce complex noise behaviors.

Purpose of the Study:

• To investigate the characteristics of random-telegraph-like noise (RTN) in ReRAM structures induced by programming pulses.
• To elucidate the underlying physical mechanisms responsible for RTN generation and its temporal evolution.
• To explore the potential for reversible defect dynamics to cause sustained conductance oscillations.

Main Methods:

• Experimental application of programming and 'repair' pulses to ReRAM devices.
• Detailed analysis of RTN patterns, including frequency and amplitude correlations.
• Atomistic simulations of ReRAM structures to model defect behavior and conductance modulation.
• Correlation of simulation results with experimental observations of current pulses.

Main Results:

• Single programming pulses induce highly correlated RTN patterns that change with each pulse.
• Weaker 'repair' pulses do not effectively reduce RTN frequency or amplitude.
• Atomistic simulations reveal semiperiodic current pulses attributed to reversible point defect oscillations.
• These oscillations modulate the conductance of the electro-formed channel in ReRAM.

Conclusions:

• RTN in ReRAM is linked to reversible oscillations of point defects within the conductive channel.
• This study provides the first report of sustained conductance oscillations caused by reversible configuration changes in VCM cells.
• The findings offer insights into ReRAM noise mechanisms and potential pathways for device improvement.