Deposition techniques of c-axis-tilted ScAlN films by conventional RF magnetron sputtering

It is difficult to synthesize c-axis tilted ScAlN films by using co-sputtering, because unidirectional oblique incident of sputtered particles is needed to obtain c-axis tilted structure. To realize the oblique incident, single source sputtering technique was proposed for c-axis tilted film deposition. ScAl alloy target was used to achieve ScAlN film synthesis instead of co-sputtering. As a result, c-axis highly tilted ScAlN film (tilt angle =33°) was obtained by using this deposition technique. From the result of film transducer loss measurement, we found that longitudinal and shear elasticity of AlN decreases by adding Sc. c-axis highly tilted ScAlN film showed giant k₁₅´ values of 0.32 in spite of its low degree of orientation.