PIEZORESISTIVE CANTILEVER FOR ATOMIC FORCE MICROSCOPY

摘要

A microminiature cantilever structure is provided having a cantilever arm with a piezoresistive resistor embedded in at least the fixed end of the cantilever arm. Deflection of the free end of the cantilever arm produces stress in the base of the cantilever. That stress changes the piezoresistive resistor's resistance at the base of the cantilever in proportion to the cantilever arm's deflection. Resistance measuring apparatus is coupled to the piezoresistive resistor to measure its resistance and to generate a signal corresponding to the cantilever arm's deflection. The microminiature cantilever is formed on a semiconductor substrate. A portion of the free end of the cantilever arm is doped to form an electrically separate U-shaped piezoresistive resistor. The U-shaped resistor has two legs oriented parallel to an axis of the semiconductor substrate having a non-zero piezoresistive coefficient. A metal layer is deposited over the semiconductor's surface and patterned to form an electrical connection between the piezoresistive resistor and a resistance measuring circuit, enabling measurement of the piezoresistive resistor's resistance. Finally, the semiconductor substrate below said cantilever arm is substantially removed so as to form a cantilevered structure, and a tip is connected to the free end of the cantilever arm to facilitate the structure's use in an atomic force microscope.