Evaluation of niobium effects on the longitudinal piezoelectric coefficients of Pb(Zr, Ti)O-3 thin films

Pb(Zr, Ti)O-3 (PZT) and Pb(Zr, Ti, Nb)O-3 (PNZT) thin films have been depos ited on platinized silicon substrates by sputtering followed by a postannea ling treatment. The Nb concentration in the films varied between 1 and 7 at . % with increments of 1 at. %. The effects of Nb modification on the piezo electric response, and particularly on the longitudinal piezoelectric coeff icient d(33), have been investigated. The introduction of Nb enhances the d ielectric and piezoelectric properties of the PZT films. The best doping le vel ranges from 1 up to 2 at. %. The relative dielectric constant epsilon(r ), reaches 1100, and the maximum value of d(33) is equal to 115 pm/V for a 1 at. % Nb-doped PZT in comparison to 820 and 55 pm/V for an undoped PZT fi lm. PNZT films are suitable for microsystem applications. (C) 2000 American Institute of Physics. [S0003-6951(00)03422-7].