Solution-processed high-k thin films as a resistive switching for ReRAM applications

• The RS characteristics for solution-deposited HfOx films were directly compared with sputtering-deposited HfOx films.
• The switching mechanism was discussed by using the Poole–Frenkel emission model.
• Furthermore, the RS properties of solution-deposited TaOx films were investigated, to expand the validity of solution-processed high-k materials for practical use in diverse ReRAM applications.

Resistive switching characteristics of solution-processed high-k thin films (HfOx and TaOx) were investigated for ReRAM applications. The thickness of solution-processed high-k thin films can be easily controlled by simple spin coating. We optimized the critical thickness of solution-processed HfOx and TaOx thin films, for reliable ReRAM operations. A similar bipolar resistive switching behavior was observed from both solution-processed and sputter-processed HfOx films. Furthermore, it was found that the solution-processed HfOx and TaOx films have a uniform resistive switching characteristic. The dominant conduction of these solution-processed films is described by Ohmic conduction in the low-resistance state. On the other hand, Ohmic conduction at low voltage and Poole–Frenkel emission at high voltage dominate in the high-resistance state. It was verified that the solution-processed HfOx and TaOx films have superior endurance and retention characteristics. Therefore, ReRAM devices based on solution-processed high-k materials are expected to be a promising candidate, for usage of resistive memory in glass substrate or flexible substrate based electronic devices.