Sputter deposition and characterization of “epi-poly” Pb(Zr, Ti)O₃ thin film on (100) Si substrate for MEMS applications

Abstract

Monocrystalline Pb(Zr, Ti)O3 (mono-PZT) thin films are suitable for specific microelectromechanical systems applications. However, these films are more brittle than general polycrystalline PZT thin films. Herein, we focus on an epitaxial PZT thin film with multiple variants in the in-plane direction. Such a unique crystalline structure is expected to have properties intermediate between the mono- and polycrystalline PZT thin films. Such a film is called as “epi-poly” thin film in this paper. We formed an LaNiO3 buffer layer with three variants as an underlayer. PZT was then sputter-deposited onto it. Thus, a (100)-oriented epi-poly PZT thin film with three variants was obtained. Its piezoelectricity, ∣e 31,f ∣, dielectric constant, ε r33, dielectric loss, and tanδ were measured to be approximately 9 C m−2, 750–800, and 0.02, respectively. Nano-indentation tests on the epi-poly and mono-PZT thin films indicated that the former had superior mechanical robustness than that of the latter.

Fabrication and characterization of monocrystalline-based composite Pb(Zr, Ti)O3 thin film patterned with a polycrystalline crack stopper structure

“…This direction is the most brittle as reported in Ref. 29. As a result, cracks from the indentation were generated.…”

“…28) Techniques for locally growing epitaxial PZT thin films with different in-plane orientations have also been developed. 29,30) These films proved to be more mechanically robust than the mono PZT thin films. However, in each case the a-axis orientation prevailed, resulting in films with lower piezoelectric constants, higher dielectric constants and reduced figures of merit compared to highly crystalline Mono-PZT thin films.…”

An investigation of the Vickers hardness of polishing pads using simulations based on microtomography model

“…( 5) and ( 6), following the guidelines of ASTM E92-16 (2016) standards. In these equations, F symbolizes the applied load in kilograms-force, and D represents arithmetic mean of the two diagonals lengths of the indentation mark (D 1 and D 2 ) measured in millimeters, [33][34][35] as illustrated in Fig. 7(b).…”