Fabrication of Bevel Structures by Means of the Spatial Gradient of Ion Dose in Ar Gas Cluster Ion Beam and Its Unique Characteristics

For the accurate characterization of organic layered structures, a novel methodology to fabricate the bevel structure is suggested by utilizing the argon cluster ion-beam sputtering (Ar GCIB), namely, little chemical damage to the organic material and a spatial gradient of ion dose in the sub-millimeter range. The Ar GCIB sputtering settings are elaborately tuned on the basis of the Faraday/target current, and its optimization condition for preparing the bevel structure is determined. As a standard sample, an organic bevel structure is manufactured from the organic layered structure of C₆₀/boron subphthalocyanine chloride/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) films, and their molecular distributions and chemical/electronic structures are investigated using various analytical techniques, including X-ray photoelectron spectroscopy, secondary ion mass spectrometry, Auger electron spectroscopy, Raman spectroscopy, and matrix-free ultraviolet-laser desorption/ionization. Every experimental result demonstrates clearly that the bevel structure prepared by the method keeps its original molecular distribution and chemical structure. On the contrary, conventional etching techniques such as Ar⁺ ion beam, focused ion beam, and ion milling cause critical distortion in chemical information without exception. Ultimately, the suggested method, a unique way to prepare a damage-free organic bevel structure, widens the availability of analytical techniques that have limitations in spatial or depth resolution.