A nondestructive technique for determining the spring constant of atomic force microscope cantilevers

We present a simple, accurate, and nondestructive method to determine cantilever spring constants by measuring the resonant frequency before and after the addition of a thin gold layer. The method for resonating the cantilevers uses electrostatic force modulation, which has been described for conductive cantilevers, but we demonstrate it can also be applied to silicon nitride cantilevers. The variations in spring constant for cantilevers of the same type across the same wafer are also explored.