Methods of forming films including scandium at low temperatures using chemical vapor deposition to provide piezoelectric resonator devices and/or high electron mobility transistor devices

-20. (canceled)

-31. (canceled)

-34. (canceled)

An RF integrated circuit device comprising:

• a substrate;
• and
• a High Electron Mobility Transistor (HEMT) device on the substrate including a ScAlN layer including a concentration of C that is less than 1019/cm3 and configured to provide a barrier layer of the HEMT device to confine formation of a 2DEG channel region of the HEMT device.

-39. (canceled)

The RF integrated circuit device of claim 37 wherein the substantially uniform composition of wurtzite crystalline structure ScAlN is substantially free of segregated ScN crystal structures as illustrated in FIG. 4.

-47. (canceled)

A piezoelectric acoustic resonator layer comprising:

• a substrate;
• an MOCVD formed single crystal piezoelectric ScxAl1-xN layer on the substrate, where x is in a range between about 0.04 and about 0.41.

A method of forming a piezoelectric acoustic resonator layer, the method comprising:

• providing a substrate in a MOCVD reactor chamber;
• forming an MOCVD single crystal piezoelectric ScxAl1-xN layer on the substrate, where x is in a range between about 0.04 and about 0.41.