The Impact of Electrostatic Interactions Between Defects on the Characteristics of Random Telegraph Noise

Random telegraph noise (RTN) is one of the most challenging defect-related reliability concerns in emerging HfO2-based devices due to the higher bulk defect density compared to SiO2. Despite many research efforts, the physical mechanisms determining complex signals (e.g., multilevel, anomalous, temporary RTN) are still unclear and need a deeper investigation. With this driving force, we performed physic-based kinetic Monte Carlo (kMC) simulations in a TiN/HfO2/TiN cell to directly analyze the role of defects which promote RTN, both in steady state and transient regime. The nonmonotonic trends of the ratio of the RTN dwell times with the applied bias frequently found in the literature are found to be caused by changes with the applied voltage of the preferential capture/emission source/destination of traps. The in-depth analysis sheds new light on the conventional methods for defect classification and vertical position estimation. Moreover, such source/destination changes also occur over time due to the dynamics of the local electric field, which varies with the evolution of the surrounding electrostatic landscape. Notably, the local field is given by the overlap of the applied voltage and of the trapped charge contributions, the latter being dominant at low voltages. The analysis of the Markov chains of closely spaced defects shown interdependencies and alterations of the RTN capture and emission times. A new method is proposed to include the impact of electrostatic interactions between defects on RTN.