Forming-Free Reversible Bipolar Resistive Switching Behavior in Al-Doped HfO2 Metal–Insulator–Metal Devices

Abstract

Resistive switching (RS) characteristics are investigated in fabricated Al-doped HfO2 metal–insulator–metal devices. It is proposed that oxygen vacancies in Al-doped HfO2 devices play a key role as electron trap centers, leading to the forming-free reversible bipolar resistance switching behavior. The conduction mechanism can be explained by electron trapping and detrapping from such oxygen vacancy-related traps in the Al-doped HfO2 films and is dominated by a trap-controlled space-charge-limited current (SCLC) mechanism. A large RS ratio (~106) and excellent retention characteristics are also observed at room temperature as well as at 85°C. Such devices have potential for application in nonvolatile random-access memory.