Focused ion-beam patterning of nanoscale ferroelectric capacitors

A 50 kV Ga+ focused ion beam was applied for milling submicron Pt-(La0.5Sr0.5) CoO3-Pb(NbxZryTiz)O 3-(La0.5Sr0.5)CoO3-Pt-based ferroelectric capacitor heterostructures prepared by pulsed laser and sol-gel deposition techniques. The milling yields were found to be 0.22±0.02 μm3/nC for Pb(NbxZryTiz)O3, 0.3.4±0.01 μm3/nC for (La0.5Sr0.5)CoO3, and 0.34 ±0.06 μm3/nC for Pt layers. The influence of the ion beam current and its scan strategy, as well as depth of milling, on the quality of fabricated structures was studied. The minimum sizes down to 0.017 μm2 for the top electrode, and 0.04 μm2 for the capacitor structures milled to the bottom electrode were achieved without an additional sacrificial layer. A scanning probe microscopy technique was employed to test the properties of the milled capacitor structures. © 1998 American Vacuum Society.