Field cycling behavior and breakdown mechanism of ferroelectric Al0.78Sc0.22N films

The effects of field cycling of Al0.78Sc0.22N capacitors on ferroelectric properties are investigated. In the first hundreds of switching cycles, the reduction in the switching voltage was observed, possibly due to the formation of nitrogen-vacancy to facilitate the atom displacements. With further switching cycles, fatigue effect was observed, especially for domains with low switching voltage. The leakage current analysis indicates continuous downward band bending with the number of switching cycles, effectively reducing the Schottky barrier height for electrons. The breakdown of Al0.78Sc0.22N films is triggered by the Joule heat due to excessive leakage current. The mechanism is in contrast to conventional ferroelectric materials, where the breakdown is triggered by Joule heat at the local conductive filaments.

Automated summary

The effects of field cycling on ferroelectric properties of Al0.78Sc0.22N capacitors were investigated. The research found that in the early switching cycles, the switching voltage decreased, possibly due to the formation of nitrogen-vacancy facilitating atom displacements. Fatigue effect was observed in further switching cycles, especially in domains with low switching voltage. Leakage current analysis showed a continuous reduction in the Schottky barrier height for electrons with increasing number of switching cycles. The breakdown of Al0.78Sc0.22N films was triggered by excessive leakage current causing Joule heat.