Electrical properties of PZT-PCW thick film on Pt/Sic/Si, and structural stability of SiC

Abstract

We have fabricated the PZT-PCW thick films on Pt/(Ti, Pt, and TiO2)/SiNx/SiC/Si substrates. SiC thick films were deposited on the Si substrate by thermal CVD method. SiNx films with different film thickness as a diffusion barrier layer were deposited on SiC/Si substrates using plasma enhanced chemical vapor deposition. The bottom electrode used was double layers of Pt/(Ti, Ta, and TiO2). We used TiO2, Ti, and Ta as a buffer layer to improve the adhesion property of Pt film. PZT-PCW thick films were prepared on the SiC thick films by screen printing. All samples were quickly introduced into the furnace, kept at a temperature between 750 and 950degrees for 10 min, and then cooled in air. For application of cantilever based device, SiC thick film was used as a supporting material in order to improve sensing sensitivity of cantilever based sensor. However, in order to use SiC thick films, we needed to investigate interfacial properties between PZT and SiC thick films. We investigated the structural stability of the adhesion layer (Ti, TiO2, and Ta) and the diffusion barrier layer (SiNx) using the PZT-PCW thick films with different layers. The PZT-PCW thick film with TiO2 as adhesion layer showed more stable interface than that with Ti and Ta below 900degreesC. In the case of the PZT-PCW thick film with SiNx layer, SiNx films showed more stable interface at the thickness of 3000 to 6000 A. In the case of PZT-PCW thick film with the SiNx thickness of 6000 Angstrom, the electrical properties were improved with the increase of sintering temperature. In case of the PZT-PCW thick film with sintered at 950degreesC, the remanent polarization (P-r) was about 13.0 muC/cm(2) at the applied field of 150 kV/cm, and the dielectric permittivity (epsilon(r)) was 551 at the frequency of 100 kHz.