Publications

Sc(0.06)Al(0.94)N film evaluation using contour mode resonators

Griffin, Benjamin G.; Henry, Michael D.; Heinz, Bernd

Recent literature has focused on improving piezoelectric coupling coefficients by alloying aluminum nitride (AlN) with scandium (Sc). Akiyama et al. showed the highest d-33 piezoelectric coefficient increase of >4x at a 41% Sc substitution for Al. Thus far, studies mainly focus on material measurements such as x-ray diffraction or piezoelectric constants to assess the material quality. Although these measurements are useful to assess the improvement in the piezoelectric performance of the material, they do not address improvements in the figure-of-merit (FOM) of resonators (i.e., coupling coefficient times quality factor). Resonator structures are needed to directly extract these key performance parameters for film assessment. Fabrication integration, however, must be minimized to avoid obscuring film performance by extrinsic device effects.