Improvement in the electrical properties in Pt/Pb(Zr0.52Ti0.48)O3/Pt ferroelectric capacitors using a wet cleaning method

Abstract

A wet cleaning solution was designed to specifically eliminate nonferroelectric phases, such as pyrochlore, PbO, and the etching damaged layer. Scanning electron microscopy pictures clearly showed that treatment with the cleaning solution completely removed these nonferroelectric phases. After removing the nonferroelectric phases, ferroelectric properties such as remnant polarization, coercive voltage, and leakage current, were remarkably improved. In addition, the wet cleaned ferroelectric capacitors yielded superior endurance against hydrogen-induced damage compared to those of the noncleaned capacitors.

An optimized one-step wet etching process of Pb(Zr0.52Ti0.48)O3thin films for microelectromechanical system applications

“…With the common methods of dry etching processes including ion beam etching and reactive ion etching, it is difficult to obtain satisfactory PZT patterns due to the different sputtering rates of Pb, Zr and Ti. Although patterning PZT by dry etching has been reported, a degradation of the electrical properties of the PZT film was found, which resulted from re-deposition species formed on the sidewall and the local stresses caused by the bombardment during PZT etching in plasma [6,7]. In addition, the selectivity of PZT over the photoresist and Pt bottom electrodes is relatively poor.…”

Selective Growth and Micropatterning Technique for Oxide Thin Films by Sacrificial a-CaO Layer

“…The standard method is performed by transferring the pattern of the photoresist prepared by conventional photolithography or e-beam lithography to the oxides through top-down approaches via wet etching and dry etching. [3][4][5][6][7][8][9][10][11] Both etching procedures have advantages and disadvantages to the quality of patterned oxides. In the case of wet etching, the advantage is that some etchants are material selective, whereas the disadvantage is its isotropic property, leading to a common problem of under-etch of patterned oxides.…”

Submicron patterning of epitaxial PbZr0.52Ti0.48O3 heterostructures

“…The wet chemical etching is one of the most widely used methodologies for patterning of PZT which uses a buffered solution of corrosive hydrofluoric acid (HF) together with hydrochloric acid (HCl) and nitric acid (HNO 3 ). [6][7][8][9][10][11][12] Several major problems were encountered while etching PZT films with strongly acidicsolutions through photoresist masks such as production of lead-rich residues, 6,10 high under-etching and heavy brim damage, 7,11 attack of etchant acids to pre-existing device components underneath PZT, 11 and degradation of ferroelectric properties in post-etched films. 9 Although intensive research was performed to improve the wet-etching procedure using multiple chemical treatments 6,9,10 of post-etched films, the enhanced possibility of contamination in successive steps still remains a concern.…”