Pulsed laser deposition of multilayer TiN/Pb(ZrxTi1-x)O-3 for piezoelectric microdevices

Multilayer Pb(ZrTi)O-3 (PZT)/TiN/Si structures were grown by two subsequent laser ablation processes in reactive atmosphere. First, a fee-oriented TiN film was deposited by laser ablation of a Ti target in high-purity nitroge n reactive gas. Subsequently, a crystalline, piezoelectric PZT film was gro wn by reactive ablation of a PZT target in oxygen atmosphere. Both depositi on processes were conducted at quite low Si(100) substrate temperature: 350 degrees C for TiN and 370 degrees C for PZT, in the same experimental setu p (Nd-YAG laser, lambda = 1060 nm, energy/pulse 0.3 J, t(FWHM) = 10 ns). Ti N film properties were analyzed by XRD and electric measurements. After the deposition of the PZT layer, the obtained structure was first characterize d by XRD, SEM and SIMS techniques. Testing measurements performed after the deposition by thermal evaporation of an Al layer as top electrode on the P ZT/TiN/Si structure confirm that they can be used as sensor transducer elem ent. The TiN (as high conductive nitride) layer replaces the former Au laye r used as bottom electrode. In this way, the Au diffusion inside the Si sub strate, as well as in the deposited layer, is avoided, as could be observed from a comparative study of the SIMS spectra recorded for PZT/TiN/Si and P ZT/Au/Si configurations. (C) 1999 Elsevier Science S.A. All rights reserved .