*3.2. Dielectric Properties Measurement*

We performed I−V and C−F tests on Pt samples. The scanned voltage from the I-V test does not exceed the coercivity field of the film in order to observe the leakage current of the device. The leakage current of the Pt sample is small as can be seen in Figure 5a. The currents in the positive and negative directions are not symmetrical, which is caused by the Schottky contact between Pt and AlScN and the ohmic contact between Al and AlScN. [22] As shown in Figure 5b, in the C-F test, the frequency was scanned from 1 kHz to 5 MHz, the measured capacitance value increased from 10 pF to 18 pF, and the area of the device under the test was 4 <sup>×</sup> <sup>10</sup>−<sup>4</sup> cm<sup>2</sup> .

**Figure 5.** *Al*0.7*Sc*0.3*N* with Pt as the bottom electrode. (**a**) I−V curve with voltage scanning from 0 V to 50 V and then returning to 0 V, similar in the negative direction. (**b**) The C−F scan goes from 1 kHz to 5 MHz and back.
