A Study on the Ferroelectric Tunnel Junction Devices based on HfZrO2

Abstract

For the computing system to advance, it is required to develop memory devices with innovative switching mechanisms in terms of hardware. Among the device candidate groups of various switching mechanisms, ferroelectric material-based devices are attracting attention. The ferroelectric materials have the property of maintain polarization even when an external electric field disappears, and can be manufactured as a low-power, non-volatile memory. In addition, theoretically, it can be up to 220 ps switching speed, which has the advantage of having a fast reaction speed. Ferroelectric devices are classified into Ferroelectric Random Access Memory (FeRAM), Ferroelectric Field Effect Transistor (FeFET) and Ferroelectric Tunnel Junction (FTJ) devices according to the location of ferroelectric materials. FTJ devices have advantages in terms of process and degree of integration. This study conducts experiments to implement the FTJ devices with a Metal-Ferroelectric-Metal (MFM) structure based on ferroelectric materials. In order to induce interface-limited conduction mechanism in the MFM structure, precursor purge time, oxygen injection pressure and oxygen purge time among Atomic Layer Deposition (ALD) parameters are adjusted during HfZrO2 deposition. Tunneling showed in the ferroelectric thin film by increasing the oxygen injection pressure, and the Tunneling Electroresistance (TER) value increased by increasing the oxygen and precursor purge times. In the TiN/HfZrO2/W structure device, the TER value was ensured to 16 when the precursor purge time and oxygen purge time were long and the oxygen injection pressure was 30 %.