A METHOD FOR DETERMINING THE SPRING CONSTANT OF CANTILEVERS FOR ATOMIC-FORCE MICROSCOPY

Cantilevers fabricated by means of micromachining techniques are usual ly used for atomic force microscopy. In this paper, the spring constan t of an atomic force microscope (AFM) cantilever is determined by usin g a large-scale cantilever. Since the spring constant of the large-sca le cantilever is calibrated accurately, the spring constant of the AFM cantilever is determined precisely by measuring the deflections of bo th cantilevers simultaneously using heterodyne interferometry. The slo pe of the force curve gives the spring constant of the AFM cantilever. It is not necessary to measure the dimensions of the AFM cantilever i n the proposed method. Although this method is simple, the spring cons tant of the AFM cantilever is obtained accurately.