Improvement of piezoelectric properties of epitaxial (K,Na)NbO₃ thin films grown on Si substrates

Abstract Lead-free epitaxial (K 0.47 Na 0.53 )NbO 3 (KNN) thin films were fabricated on (001)SrRuO /Pt/ZrO 2 /Si substrates by RF magnetron sputtering at 650 °C and post-annealed the same a rapid thermal annealing (RTA) process. The crystal structure of KNN changed RTA, i.e. lattice parameter c in out-of-plane direction decreased instead an increase in-plane direction. displacement–electric field curve RTA-annealed was symmetrical shift polarization reversal smaller than annealed conventional furnace. This means that RTA is effective compensating for oxygen vacancies as well suppressing generation A-site interface between film substrate. converse piezoelectric coefficient ∣ e 31, f KNN/Si unimorph cantilever found to improve up 7.7 C m −2 due decrease defect density resulting from RTA.