Single-step electrochemical machining of complex nanostructures with ultrashort voltage pulses

We show that complex patterns including three-dimensional structures, lines, curved features, and arrays can be machined in substrates in single-step processing without the need for rastering. High-aspect-ratio nanometer accurate features were machined in nickel using ultrashort voltage pulse electrochemical machining. Experiments were conducted with two different tool shapes. The first was a combination of rectangles, squares, and a half circle; the second was a 2×2 array. The effect of pulse duration and electrolyte concentration on feature resolution was studied. Structures with 90 nm widths were made by applying 2 ns voltage pulses.