Abstract
Metal-deposited probes with a 13 nm tip radius for conducting scanning probe microscopy (SPM) are obtained by sputter-coating a silicon cantilever with platinum on a single side. By optimizing the metal layered structure and the film stress, the silicon cantilever, whose spring constant and resonant frequency are 2 N/m and 70 kHz, respectively, is freestanding without bending. Besides the cantilever bending, curling of the probe apex was monitored and minimized in the series of the experiments conducted. The relatively soft probe apex was another part of the cantilever chip that was deformed by the metal film stress because the basic silicon tetrahedral probe was thin and inclined against the normal direction of the cantilever. In the final process, aluminum was deposited as a reflex coating on the back side of the silicon cantilever by vacuum evaporation because the light-reflectance was twice as high as that for platinum coating. The sharp probe apex, good conductivity of precious-metals and high reflection contribute to high-resolution conduction SPM measurements.