Double cantilever sensor for atomic force microscope

Abstract

An atomic force microscope that performs both atomic force and surface potential measurements on a sample comprises a conductive probe beam that includes two segments, a first segment exhibiting a first mechanical resonant frequency and a second segment exhibiting a second different mechanical resonant frequency. An actuator causes oscillations in the probe beam at the first mechanical resonant frequency. An oscillator applies to the probe beam a signal having a frequency equal to the second mechanical resonant frequency. Due to the potential difference between the probe beam and the sample, a force results that causes the probe beam to vibrate. The probe beam is moved over the sample's surface in a direction parallel to the surface. An optical heterodyne system senses movements of the probe beam at both the first and second resonant frequencies and provides an output signal indicative of the second resonant frequency movement of the probe beam's second segment. In a further embodiment, second and third harmonics of the second resonant frequency are applied to the probe beam and enable the measurement of capacitance changes between the probe beam and the sample surface and changes in capacitance with respect to voltage over the sample' s surface.

Dependencies are inferred from the claim text.