Reliable Accessibility of Intermediate Polarization States in Textured Ferroelectric Al_0.66Sc_0.34N Thin Film

Ferroelectric materials are promising candidates for neuromorphic computing synaptic devices due to the nonvolatile multiplicity of spontaneous polarization. To ensure a sufficient memory window, ferroelectric materials with a large coercivity are urgently required for practical applications in highly scaled multi-bit memory devices. Herein, a remarkable reliability of intermediate ferroelectric polarization states is demonstrated in a textured Al0.66Sc0.34N thin film with a coercive field of 2.4 MV cm(-1). Al0.66Sc0.34N thin films are prepared at 300 degrees C on Pt (111)/Ti/SiO2/Si substrates using a radio frequency reactive sputtering method. Al0.66Sc0.34N thin films exhibit viable ferroelectricity with a large remanent polarization value of >100 mu C cm(-2). Through the conventional current-voltage characteristics, polarization switching kinetics, and temperature dependence of coercivity, the reproducibility of multiple polarization states with apparent accuracy is attributed to a small critical volume (3.7 x 10(-28) m(3)) and a large activation energy (3.3 x 10(27) eV m(-3)) for nucleation of the ferroelectric domain. This study demonstrates the potential of ferroelectric Al1-xScxN for synaptic weight elements in neural network hardware.