Microfabrication processes for high-J/sub c/ superconducting films

An investigation of microfabrication processes for Y-Ba-Cu-O films using ion-beam techniques is discussed. Compared with Ar ion-beam etching (IBE), Cl/sub 2/ reactive ion-beam etching (RIBE) enhanced sputtering yield at 400-V acceleration voltage. Maskless etching was carried out using a 130-keV Au/sup +/ focused ion beam (FIB) with a 0.1- mu m-diameter beam. A 50-nm-thick film was patterned into 0.3- mu m-wide lines at a dose of 5*10/sup 16/ ions/cm/sup 2/. Ion implantation with a 300-keV Si/sup ++/ FIB suggested the possibility of making submicron patterns by selectively modifying film properties from superconductive to normal. High-T/sub c/ superconducting lines as narrow as 0.8 mu m have been fabricated from epitaxial YBa/sub 2/Cu/sub 3/O/sub 7-y/ films by IBE combined with FIB lithography. The resulting lines, 1.3- mu m wide and 2-mm long, showed a zero resistance temperature of 81 K and a critical current density of 1.9*10/sup 4/ A/cm/sup 2/ at 77.3 K.<
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