Ecofriendly Water-Based Solution Processing: Preliminary Studies of Zn-ZrO2 Thin Films for Microelectronics Applications

Abstract

This paper demonstrates the high yield and cost effectiveness of a simple and ecofriendly water-based solution processing, to produce Zinc-doped Zirconia (Zn-ZrO2) composite thin films, onto glass substrates, with excellent optical properties that make them of great interest for optical and microelectronics technologies. The effect of Zn variation (given as 10, 15, 20 at.%) on the crystallization, microstructure, and optical properties of ZrO2 film was examined. The addition of Zn did not restructure the ZrO2 lattice, as the results indicated by X-ray diffraction (XRD) and Raman spectroscopy revealed neither any mixed or individual phases; rather, all the films retained the amorphousness. Nonetheless, Zn did control the grain formation at the film surfaces, thereby changing the surface morphology. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) evidenced homogeneous, compact, crack-free, and dense films with surface roughness below 2 nm indicating smooth surfaces. The films were highly transparent (>80%) with tunable optical band gap Eg (5.21 to 4.66 eV) influenced by Zn dopant. Optical constants such as refractive index (n), extinction coefficient (k), and dielectric constant (ε) were obtained from spectroscopic ellipsometry (SE), and a correlation was established with respect to the doping level. A high value of n > 2 value indicated high packing density in these films, and it decreased slightly from 2.98 to 2.60 (at 632 nm); whereas, optical losses were brought down with increasing Zn indicated by decreasing k values. The photoluminescence (PL) spectra showed UV emissions more pronounced than the blue emissions indicating good structural quality of all the films. Nonetheless, added defects from Zn had suppressed the PL emission. The technique presented in this work, thus, manifests as high performance and robust and has the potential comparable to the sophisticated counter techniques. Furthermore, the Zn-ZrO2 films are promising for a low-cost solution to processed microelectronics and optical technologies after reaching high performance targets with regards to the electrical properties.

Additive Manufacturing of Zn‐Doped ZrO2Architectures

“…A similar shift toward shorter wavelengths has been observed in amorphous ZrO 2 doped with Zn, attributed to introducing defect states upon doping. [ 38 ]…”

“…A similar shift toward shorter wavelengths has been observed in amorphous ZrO 2 doped with Zn, attributed to introducing defect states upon doping. [38] Interestingly, the μ-PL spectrum of the ZrO 2 annealed at 1200 °C is deconvoluted into three Gaussian contributions at 2.16 eV (575 nm), 2.43 eV (511 nm), and 2.81 eV (442 nm). Lin et al reported that V O is the principal contribution to the PL signals at 2.64 eV (470 nm) for m-ZrO 2 .…”

“…[35] Periodic density functional calculations on ZrO 2 :Zn showed the promotion of oxygen vacancies in tetragonal and monoclinic crystalline phases. [36] Moreover, the doping of ZrO 2 with Zn increments the material performance for specific applications, including superior protection against corrosion, [37] pronounced photoluminescence (PL) within the UV range, [38] or increased enhancement factor in surfaceenhanced Raman spectroscopy. [39] To our knowledge, this is the first time that ZrO 2 :Zn microarchitectures have been produced using AM methods, and it is an attempt to understand the role of phase stabilization and the type of defect associated with phase stabilization optically.…”

“…[ 35 ] Periodic density functional calculations on ZrO 2 :Zn showed the promotion of oxygen vacancies in tetragonal and monoclinic crystalline phases. [ 36 ] Moreover, the doping of ZrO 2 with Zn increments the material performance for specific applications, including superior protection against corrosion, [ 37 ] pronounced photoluminescence (PL) within the UV range, [ 38 ] or increased enhancement factor in surface‐enhanced Raman spectroscopy. [ 39 ]…”