Effect of abnormally oriented grains on the ferroelectric properties of Al0.65Sc0.35N thin films

The wide bandgap wurtzite Al1-xScxN ferroelectric material is compatible with semiconductor processes and offers advantages such as high remanent polarization (Pr) and high-temperature stability. To clear the relationship between the structure zone model (SZM), abnormally oriented grains (AOGs) and the ferroelectric properties, the Al 0.65 Sc 0.35 N films were prepared at various sputtering pressures (0.32-0.90 Pa) and substrate temperatures (200-500 degrees C) on low resistance n+-(111) Si substrate by the radio frequency dual-source reactive magnetron sputtering method using Al and Sc targets under pure N2 gas. The introduction of AOGs facilitates compressive stress reduction and promotes ferroelectric switching. However, excessive AOGs will damage the (002) orientation, leading to loss of ferroelectricity. The Al 0.65 Sc 0.35 N films synthesized under a sputtering pressure of 0.52 Pa and a substrate temperature of 400 degrees C exhibited a lower leakage current at high electric field, with a Pr value of 154.3 mu C/cm2 and a negative coercive field (Ec-) of 3.1 MV/cm at a testing frequency of 1 kHz. The outstanding comprehensive properties support the large potential of Al1-xScxN ferroelectric material for highperformance FeRAM devices.