Abstract:
An AFM (10) that combines an AFM Z position actuator (16) and a self-actuated Z-position cantilever (20) (both operable in cyclical mode and contact mode), with appropriate nested feedback control circuitry to achieve high-speed imaging and accurate Z-position measurements. The self-actuated cantilever (20) includes a Z-positioning element (36) integrated therewith and an oscillator that oscillates the cantilever (20) at a resonant frequency and at an oscillation amplitude equal to a setpoint value. The AFM includes a first feedback circuit (12) nested within a second feedback circuit (14), wherein the first feedback circuit generates a cantilever control signal in response to vertical displacement of the self-actuated cantilever (20) during a scanning operation, and the second feedback circuit (14) is responsive to the cantilever control signal to generate a position control signal.