Methods of forming group iii piezoelectric thin films via sputtering

Abstract

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).

What is claimed: 
     
         1 . A method of forming a piezoelectric thin film, the method comprising:
 providing an inert gas and a nitrogen process gas to a process chamber including a substrate and a target comprising a Group III element;   heating the substrate to a temperature in a range between about 350 degrees Centigrade and about 850 degrees Centigrade to provide a sputtering temperature of the substrate;   sputtering the Group III element from the target onto the substrate at the sputtering temperature to provide a Group III seed layer directly on the substrate;   stabilizing the process chamber;   sputtering the Group III element from the target onto the Group III seed layer at the sputtering temperature to provide the piezoelectric thin film including a nitride of the Group III element; and   forming an acoustic resonator device on the piezoelectric thin film.   
     
     
         2 . The method of  claim 1  wherein the target comprises a composite target including the Group III element as a first Group III element and including a second Group III element;
 wherein sputtering the Group III element from the target onto the substrate at the sputtering temperature to provide the Group III seed layer on the substrate comprises: 
 sputtering the first Group III element and the second Group III element from the composite target onto the substrate at the sputtering temperature to provide the Group III seed layer directly on the substrate. 
 
     
     
         3 . The method of  claim 2  wherein sputtering the Group III element from the target onto the Group III seed layer at the sputtering temperature to provide the piezoelectric thin film including a nitride of the Group III element comprises:
 sputtering first Group III element and the second Group III element from the composite target onto the Group III seed layer to provide the piezoelectric thin film including a nitride of the first Group III element and the second Group III element. 
 
     
     
         4 . The method of  claim 3  wherein the first Group III element comprises Aluminum (Al) and the second Group III element comprises Scandium (Sc). 
     
     
         5 . The method of  claim 1  wherein the Group III element comprises Aluminum (Al) or Scandium (Sc). 
     
     
         6 . The method of  claim 1  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 the inert gas in the process chamber. 
 
     
     
         7 . The method of  claim 6  further comprising:
 applying a bias to the substrate during sputtering of the Group III element from the target onto the substrate. 
 
     
     
         8 . The method of  claim 7  further comprising:
 changing a temperature inside the process chamber during sputtering of the Group III element from the target onto the substrate. 
 
     
     
         9 . The method of  claim 8  further comprising:
 changing the power applied to the cathode during sputtering of the Group III element from the target onto the substrate. 
 
     
     
         10 . The method of  claim 1  wherein heating the substrate comprises:
 heating the substrate to the temperature between about 400 degrees Centigrade to about 600 degrees Centigrade to provide the sputtering temperature of the substrate. 
 
     
     
         11 . A method of forming a piezoelectric thin film, the method comprising:
 providing an inert gas and a nitrogen process gas to a process chamber including a growth substrate and a target comprising a Group III element;   heating the growth substrate to a temperature in a range between about 350 degrees Centigrade and about 850 degrees Centigrade to provide a sputtering temperature of the growth substrate;   sputtering the Group III element from the target onto the growth substrate at the sputtering temperature to provide a Group III seed layer directly on the growth substrate;   stabilizing the process chamber;   sputtering the Group III element from the target onto the Group III seed layer at the sputtering temperature to provide the piezoelectric thin film including a nitride of the Group III element;   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.