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

We have fabricated the PZT-PCW thick films on Pt/(Ti, Pt, and TiO ₂)/SiN_x/SiC/Si substrates. SiC thick films were deposited on the Si substrate by thermal CVD method. SiN_x 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, und 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 950° 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 (SiN _x) 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 900°C. In the case of the PZT-PCW thick film with SiN_x layer, SiN_x films showed more stable interface at the thickness of 3000 to 6000 Å. In the case of PZT-PCW thick film with the SiN_x thickness of 6000 Å, the electrical properties were improved with the increase of sintering temperature. In case of the PZT-PCW thick film with sintered at 950°C, the remanent polarization (P_r) was about 13.0 μC/cm² at the applied field of 150 kV/cm, and the dielectric permittivity (ε_r) was 551 at the frequency of 100 kHz.