Effect of Titanium (Ti)-Seed and In Vacuo Process Flow on Sputtered Lead Zirconate Titanate Thin Films
Technical Report,01 Oct 2017,30 Aug 2019
CCDC Army Research Laboratory Aberdeen Proving Ground United States
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In a process improvement study to optimize a platinum Pt bottom electrode for lead zirconate titanate PZT film growth, PZT thin films were grown on Pt bottom electrodes on thermally oxidized silicon substrates. The PZT depositions on Pt were made with no underlying layer, a nucleation layer, a titanium Ti-seed layer, or a combination of nucleation on Ti-seed layer. X-ray diffraction and electrical characterization determined that a Ti-seed deposited on top of the Pt, rather than on a PZT nucleation layer, was critical to produce PZT with preferred 001 orientation while minimizing secondary phases. Best electrical performance was characterized by a dielectric constant epsilon 1150 - 100, tan delta 0.019 - 0.001 at E 0, and maximum polarization of 34.7 - 0.6 micro Ccm2 at 200 kVcm. In contrast, characterizations performed also indicate that exclusion of the Ti-seed from the PZT stack process results in dominant diffraction peaks that appear to be generated by a pyrochlore or highly strained 110 PZT phase with pinned domains.
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