Extending the Dynamic Range and Endurance of Ferroelectric Tunnel Junctions by Conductance Growth Control

We use a closed-loop algorithm to accurately program hafnium zirconium oxide (HZO) ferroelectric tunnel junctions (FTJs) to arbitrary chosen target conductance values. The key enabler is suppression of conductance growth. We have identified two different mechanisms contributing to the total conductance of FTJs. By controlling both, we demonstrated an up to threefold increase of the usable conductance range, allowing for 192 distinct states to be reliably programmed. Retention of the programmed states is independent of the absolute conductance level, allowing for 6-bit precision to be achievable for 22 min in the extended range. An additional benefit of suppressing conductance growth is a 100-fold extension of the device endurance.