Electrically induced cancellation and inversion of piezoelectricity in ferroelectric HfZrO.

HfO-based thin films hold huge promise for integrated devices as they show full compatibility with semiconductor technologies and robust ferroelectric properties at nanometer scale. While their polarization switching behavior has been widely investigated, their electromechanical response received much less attention so far. Here, we demonstrate that piezoelectricity in HfZrO ferroelectric capacitors is not an invariable property but, in fact, can be intrinsically changed by electrical field cycling.

Cycling Waveform Dependent Wake-Up and ON/OFF Ratio in AlO/HfZrO Ferroelectric Tunnel Junction Devices.

The wake-up behavior and ON/OFF current ratio of TiN-AlO-HfZrO-W ferroelectric tunnel junction (FTJ) devices were investigated for different wake-up voltage waveforms. We studied triangular and square waves, as well as square pulse trains of equal or unequal voltage amplitudes for positive and negative polarities. We find that the wake-up behavior in these FTJ stacks is highly influenced by the field cycling waveform.

Insights on the variability of Cu filament formation in the SiOelectrolyte of quantized-conductance conductive bridge random access memory devices.

Conductive bridge random access memory devices such as Cu/SiO/W are promising candidates for applications in neuromorphic computing due to their fast, low-voltage switching, multiple-conductance states, scalability, low off-current, and full compatibility with advanced Si CMOS technologies. The conductance states, which can be quantized, originate from the formation of a Cu filament in the SiOelectrolyte due to cation-migration-based electrochemical processes. A major challenge related to the filamentary nature is the strong variability of the voltage required to switch the device to its conducting state.