Parallel atomic force microscopy with optical interferometric detection

Abstract

We have developed an atomic force microscope that uses interferometry for parallel readout of a cantilever array. Each cantilever contains a phase sensitive diffraction grating consisting of a reference and movable set of interdigitated fingers. As a force is applied to the tip, the movable set is displaced and the intensity of the diffracted orders is altered. The order intensity from each cantilever is measured with a custom array of silicon photodiodes with integrated complementary metal-oxide-semiconductor amplifiers. We present images from five cantilevers acquired in the constant height mode that reveal surface features 2 nm in height. The interdigital method for cantilever array readout is scalable, provides angstrom resolution, and is potentially simpler to implement than other methods. © 2001 American Institute of Physics

The Use of Light Diffracted from Grating Etched onto the Backside Surface of an Atomic Force Microscope Cantilever Increases the Force Sensitivity

“…To conclude, we would like to mention a few papers where using of diffraction grating in combination with AFM was reported [15][16][17][18]. However, in these works a grating has been explored as an interferometer: a photodiode, placed in a certain position, measures a light intensity, which changes together with the change of the distance grating-photodiode due to the interference between the light beam directly passed via the grating (or mirror-reflected by it) and the light beam corresponding to certain (usually n = 1) diffraction order in reflection or transmission.…”

High-speed AFM and nano-visualization of biomolecular processes

“…Images (a few micrometer scan range) of a metalsemiconductor field-effect transistor were taken at a frame rate of~0.3 s/frame in constant-height mode (i.e., no feedback scan in the z-direction). This study proceeded towards the development of cantilevers with integrated sensors and/or actuators [9,10] and cantilever arrays with self-sensing and self-actuation capabilities [11][12][13]. Unfortunately, fabrication of these cantilevers could be made only in relatively large dimensions, resulting in low resonant frequencies (although higher than those of conventional tube scanners) and large spring constants.…”

Nanostructures Replicated by Polymer Molding

“…[13] The process replicates features from a photomask that is prepared by a serial lithographic technique such as electron-beam lithography, [14,15] focused-ion milling, [16][17][18] or scanning probe lithography. [19][20][21] The fabrication of masters by these techniques is slow ( 10 hr/cm 2 ) because each feature in the mask is drawn individually. The lateral dimensions of the structures that can be patterned by photolithography are limited by the wavelength of the illumination source; state-of-the-art, 157-nm sources can fabricate features as small as 50 nm.…”