Published online by Cambridge University Press: 17 March 2011
Silicon nanopillars, formed by electron beam lithography, were electrochemically etched to provide controlled size reduction. The smallest dimensions achieved were pillars of 15 nm in diameter, restricted mainly by the scanning electron microscope used for characterization. The etch rate was mainly determined by the photogeneration of carriers, by the HF concentration and by the applied voltage bias. The applied bias also controlled the resulting shape of the pillars such that a high bias resulted in etching of the pillar top whereas a negative bias caused etching only at the pillar base. For 0 V, a relatively conform etching of the pillar was observed. We discuss these phenomena in terms of electropolishing or pore formation effects on a local scale.