**3. Results and Discussions**

### *3.1. Film Quality Characterization*

As shown in Figure 4a, the full width half maximum (FWHM) of the 2*θ*/*θ* scans of the 200 nm *Al*0.7*Sc*0.3*N* films grown on Pt and Mo surfaces were 0.36◦ and 0.50◦ , respectively. The FWHM of the *ω*-rocking curve of *Al*0.7*Sc*0.3*N* (0002) peak is below 2.5◦ on Pt samples, and approximately 3◦ on Mo samples. The absence of other peaks near the *Al*0.7*Sc*0.3*N* (0002) peak indicates that the film has a good c-axis orientation [20]. The diffraction peak of the sample on the Pt surface is stronger and has a better grain orientation [21]. Comparing SEM images Figure 4b,c, there are a large number of abnormal grains of *Al*0.7*Sc*0.3*N* grown on the Mo surface. These AOGs lead to a partial or total loss of the c-axis texture in the surface layer of the films. Since the polarization direction of AlScN is along the c-axis, it can be assumed that the ferroelectric properties of the Mo sample will be worse than those of the Pt sample, which will be further verified in the later measurement.

**Figure 4.** (**a**) X-ray diffraction 2*θ*/*θ* scan *Al*0.7*Sc*0.3*N* on (**a**) Pt and (**b**) Mo. The peak of *Al*0.7*Sc*0.3*N* (0002) on the Pt sample is stronger than that of the Mo sample. SEM image of *Al*0.7*Sc*0.3*N* grown on: (**b**) Pt with a good crystal orientation; (**c**) Mo with a large number of abnormal grains.
