Effect of crystallization on the reliability of unipolar resistive-switching in HfO2-based dielectrics

• Unipolar resistive switching is compared in HfO2 and Hf0.6Si0.4O2 films.
• HfO2 films crystallize during annealing, while Hf0.6Si0.4O2 films remain amorphous.
• Electrical characteristics of HfO2 films are degraded after annealing at 600 °C.
• Electrical characteristics of Hf0.6Si0.4O2 films are unchanged by annealing at 600 °C.
• Degraded performance of annealed HfO2 films is attributed to grain boundaries.

The electroforming and unipolar resistive switching characteristics of as-deposited and annealed HfO2 and Hf0.6Si0.4O2 films are reported. The reliability of HfO2 devices is shown to be significantly degraded by annealing at 600 °C, during which the film is observed to crystallize. In contrast, the characteristics of Hf0.6Si0.4O2 devices subjected to the same annealing conditions are found to be unchanged, consistent with the fact that the films remain amorphous. These differences are attributed to the presence of grain boundaries and can have important implications for the use of HfO2 in ReRAM applications.