Methods of forming group III piezoelectric thin films via sputtering
A method of forming a piezoelectric thin film can be provided by heating a substrate in a process chamber to a temperature between about 350 degrees Centigrade and about 850 degrees Centigrade to provide a sputtering temperature of the substrate and sputtering a Group III element from a target in the process chamber onto the substrate at the sputtering temperature to provide the piezoelectric thin film including a nitride of the Group III element on the substrate to have a crystallinity of less than about 1.0 degree at Full Width Half Maximum (FWHM) to about 10 arcseconds at FWHM measured using X-ray diffraction (XRD).
1. A method of forming a piezoelectric thin film, the method comprising:
heating a substrate in a process chamber to a temperature between 350 degrees Centigrade and 850 degrees Centigrade to provide a sputtering temperature of the substrate;
and sputtering a Group III element from a target in the process chamber onto the substrate at the sputtering temperature to provide the piezoelectric thin film including a nitride of the Group III element on the substrate to have a crystallinity of less than 1.0 degree at Full Width Half Maximum (FWHM) to 10 arcseconds at FWHM measured using X-ray diffraction (XRD)
wherein the substrate comprises a growth substrate, the method further comprising:
forming a first electrode on a first surface of the piezoelectric thin film;
forming a support layer on the first electrode;
attaching a bond substrate to the support layer;
processing the growth substrate while the bond substrate is attached to the support layer to expose a second surface of the piezoelectric thin film that is opposite the first surface of the piezoelectric thin film; and
forming a second electrode on the second surface of the piezoelectric thin film so that the piezoelectric thin film is sandwiched between the first and second electrodes.
2. The method of claim 1 wherein the target comprises a first target including a first element from Group III and a second target including a second element from Group III or a single composite target including the first and second Group III elements, wherein sputtering the Group III element from the target comprises:
sputtering the first element from Group III onto the substrate and sputtering the second element from Group III onto the substrate to provide the piezoelectric thin film.
3. The method of claim 2 wherein the first element from Group III comprises Aluminum (Al) and the second element from Group III comprises Scandium (Sc).
4. The method of claim 1 further comprising:
sputtering the Group III element from the target onto the substrate at the sputtering temperature to provide a Group III seed layer on the substrate before forming the piezoelectric thin film.
5. The method of claim 4 wherein sputtering the Group III element from the target onto the substrate at the sputtering temperature to provide the Group III seed layer comprises:
applying a power to a cathode in the process chamber to generate a plasma adjacent to a surface of the target to ionize a process gas in the process chamber.
6. The method of claim 5 further comprising:
applying a bias to the substrate during sputtering of the Group III element from the target onto the substrate.
7. The method of claim 6 further comprising:
changing a temperature inside the process chamber during sputtering of the Group III element from the target onto the substrate.
8. The method of claim 7 further comprising:
changing the power applied to the cathode during sputtering of the Group III element from the target onto the substrate.
9. The method of claim 1 wherein heating the substrate comprises:
heating the substrate to the temperature between 400 degrees Centigrade to 600 degrees Centigrade to provide the sputtering temperature of the substrate.