Résumé
Ta-modified lithium niobate (LiNb 1-x Ta x O 3) thin films were deposited on ITO-covered Si(111) substrates by r.f. sputtering. Experimental results reveal that Ta content (0<x<0.75) influences strongly the grain size as well as the ferroelectric and piezoelectric properties of the deposited materials. Increasing Ta induces a significant decrease of the grain size, while the polarization capability and the piezoelectric activity decrease. The film crystallinity and preferential orientation can be enhanced by the use of a two-steps growth process.