Effects of the compliance current in the electroforming process of HfO2-based ReRAM devices

Electroforming is the activation process of ReRAM devices that initiates the resistive switching response by creating filamentary conduction paths in the oxide film. This step is fundamental for the proper operation of the device, and it is controlled by a compliance current (Ic) that prevents the hard dielectric breakdown of the ReRAMs. In this work, we study the influence of this current during the electroforming process and operation in HfO2-based ReRAM devices of different areas. Some parameters from the IV curve were extracted and analyzed to understand how the process could affect the device’s performance. We found a maximum value of Ic needed to form the CF independent of the area device that does not provoke significant changes in the electrical behavior.

I. Introduction

The ReRAM is a nonvolatile memory device studied due to the favorable characteristics that could allow it to replace flash memory technology [1]. These devices have a metal-insulator-metal structure whose operating principle relies on resistive switching controlled by an external voltage [2]. After fabrication, these devices are in a highly resistive state, called a pristine state. They need to be activated by an electroforming process that creates a conductive filament (CF) inside the insulator that connects the electrodes. During operation, the ReRAM can change between a high resistive state (HRS) and a low resistive state (LRS) due to the local changes inside the CF. Indeed, electroforming is a critical step for the functioning of the ReRAM devices because it determines the switching characteristics, especially the resistance, during the HRS and LRS.