Preparation and evaluation of sub-100 nm Pb(Zr,Ti)O₃ films derived from modified sol-gel solutions for low-voltage operation of feram

Abstract

2001) Preparation and evaluation of sub-100 nm Pb(Zr,Ti)O 3 films derived from modified sol-gel solutions for low-voltage operation of feram, Sub-100 nm PbZr0.3Tb.703 (PZT) films were prepared on WSi02/Si substrates ftom modified sol-gel solutions without using any seeding layers. Firstly, we studied Pb content [Pb/(Z#Ti)] dependence of 90-nm-thick films. In the wide Pb content region of 108 -125%, the films had perovskite-single-phase fine columnar grains with (1 1 l)-orientation and no voids. Electric properties were dependent on Pb content. The film with good microstructure, rectangular hysteresis, high remanent polarization (PJ, and low leakage current was gained for Pb content of 1 16%. Secondly, we studied film thickness dependence of PZT( 1 16/30/70) films. Films from 90 down to 61 nm in thickness were prepared. We found that the sub-100 nm films with good microstructures could be prepared h o r n the modified solutions. The sub-100 nm films had saturation voltage of 1.25 V and high P, even at 1 V or less. In particular, a 61-nm-thick film had high P, of 17 pC/cmZ at 0.75 V.