Effects of lanthanum nitrate buffer layer on the orientation and piezoelectric property of Pb(Zr,Ti)O3 thick film

Highly oriented Pb(Zi-,Ti)O-3 (PZT) films were deposited on Pt/Ti/SiO2/Si substrates by the sol-gel method using, lanthanum nitrate as a buffer layer. When the lanthanum nitrate buffer layer was heat treated at temperatures between 450 and 550 degreesC, the PZT layer coated onto this buffer layer showed a strong (100) preferred orientation. Regardless of the other deposition conditions, such as the pyrolysis temperature, pyrolysis time, annealing temperature and heating rate, the film deposited on the buffer layer had this orientation. Thick films were also fabricated using the sol-gel multi-coating method, and the (100) texture was found to be maintained up to a thickness of 10 mum. The ferroelectric hysteresis and piezoelectric coefficient (d(33)) of highly oriented PZT thick films were characterized, and the (100) oriented PZT film showed higher piezoelectric property than the (111) oriented film.