Preparation of YBa₂Cu₃O_7-δ Micropatterns Using Metal–Organic Deposition with Electron Beam

Abstract

We investigated microfabrication using the metal-organic deposition (MOD) process with an electron beam. Metal naphthenates in the irradiated area remained after development, which indicates negative exposure characteristics. The optimized electron dose was estimated to be 3400 mC/ cm 2 . Drawn patterns shrink after heat treatment because of the vaporation of organic components. A fine line with a width of 90 nm was successfully obtained after heat treatment. Numerous voids were observed on the surface of the large patterned film, compared with unirradiated films. Electron beam irradiation decomposed metal naphthenates, and cohesion was promoted by the annealing process. The optimization of the annealing profile is required to prepare uniform micropatterns. #

Preparation of YBa2Cu3O7-δ Patterned Film Using Metal Organic Deposition with Electron Beam Irradiation

“…Data for metal naphthenate precursors is also shown for comparison. 18) The film thickness for the metal octylates increases with electron dose and becomes saturated above 1500 C/cm 2 . Thus, the metal octylates can be irradiated with a smaller dose than that required to expose the metal naphthenates.…”

“…Recently we have succeeded in preparing YBCO films with epitaxial and fine line patterns (90 nm width) using metal naphthenates, SrTiO 3 (001) (STO) substrates, precisely controlled O 2 partial pressure and this EB irradiation technique. 18) However the resistivity of the fabricated YBCO wire was high and a superconducting transition was not observed.…”

Preparation of epitaxial yttrium–iron garnet micropatterns using metal–organic decomposition with electron-beam irradiation

“…In addition, it has been reported that some precursor materials for MOD have electron-beam (EB) sensitivity. [1][2][3][4][5] The precursor films reacted with high-energy electrons and showed negative exposure characteristics. Some research groups fabricated functional metal-oxide micropatterns by an MOD method with EB irradiation using EB lithography (EBL) systems and succeeded in obtaining good physical properties.…”

“…3) Tanabe et al fabricated YBa 2 Cu 3 O 7 micropatterns and succeeded in observing the superconductive transition. 4,5) This method can decrease drastically the number of fabrication steps for functional metal-oxide micropatterns, since only the EB-irradiation process is added to the conventional MOD method. Thus, this technique is very useful for forming micropatterns of various functional metal oxides using EBL systems, because it is difficult to etch functional metal oxides by a dry etching process.…”

“…This feature is similar to those of other metal octylates and naphthenates. [1][2][3][4][5]14) Okamura and Shiosaki reported that the EB sensitivity of the metal octylates for SrBi 2 TaO 9 was 1.9 × 10 3 µC=cm 2 , 14) and Tanabe et al reported that, for YBa 2 Cu 3 O 7 , it was 1.5 × 10 3 µC=cm 2 , 5) when the acceleration voltage was ∼30 kV. Thus, the EB dose required to expose our precursor materials is approximately one order of magnitude larger than that required to expose the metal octylates for SrBi 2 TaO 9 and YBa 2 Cu 3 O 7 .…”