A versatile atomic force microscope integrated with a scanning electron microscope

Abstract

A versatile atomic force microscope (AFM), which can be installed in a scanning electron microscope (SEM), is introduced. The flexible design of the instrument enables correlated analysis for different experimental configurations, such as AFM imaging directly after nanoindentation in vacuum. In order to demonstrate the capabilities of the specially designed AFM installed inside a SEM, slip steps emanating around nanoindents in single crystalline brass were examined. This example showcases how the combination of AFM and SEM imaging can be utilized for quantitative dislocation analysis through the measurement of the slip step heights without the hindrance of oxide formation. Finally, an in situ nanoindentation technique is introduced, illustrating the use of AFM imaging during indentation experiments to examine plastic deformation occurring under the indenter tip. The mechanical indentation data are correlated to the SEM and AFM images to estimate the number of dislocations emitted to the surface.

An atomic force microscope integrated with a helium ion microscope for correlative nanoscale characterization

“…Prohibitively large instruments with optical readout are difficult to integrate into electron or ion microscopes and re-alignment of the optics is very impractical, as it requires the user to vent the chamber. Using self-sensing readout addresses these concerns [5,10,17] and also significantly improves the usability of the correlative instrument for users outside of the AFM community. The reported AFM uses silicon cantilever probes with boron-doped 1 kΩ sensing elements, connected in a Wheatstone bridge configuration with aluminum tracks [20,21] and with single crystal diamond (SCD) tips that are commercially available (SCL-SensorTech Fabrication GMBH, Vienna, Austria).…”

“…The prototype tip-scanning AFM scan head is designed explicitly for correlative analysis inside electron and ion-beam microscopes. Unlike sample scanning solutions [ 9 , 16 ], where the sample is raster-scanned relative to a stationary cantilever, a tip-scanning configuration [ 10 , 17 ] requires no alteration of the sample stage and has the advantage of having the sample stationary within the field of view of the HIM during AFM imaging. The scanner is a flexure design with serial kinematics [ 18 ] and the cantilever is mounted at the end of a low-profile protruding z -flexure, which fits seamlessly between the pole piece and the sample.…”

Atomic Force Microscopy Imaging in Turbid Liquids: A Promising Tool in Nanomedicine

“…The installation of strain sensors directly into the cantilever is of particular interest as it offers several advantages over techniques with external readout. Some of the most important advantages are: (i) extremely small cantilevers far below the optical diffraction limit to increase sensitivity and so imaging speed can be realized [ 32 , 33 ], (ii) avoiding interference with photosensitive samples, (iii) the possibility of multi-cantilever arrays [ 34 , 35 , 36 ] and (iv) combining AFM with other techniques, such as scanning electron microscopy (SEM) [ 37 , 38 , 39 , 40 ]. In addition to the new readout method, advances in microfabrication have allowed the direct integration of actuators on the cantilever, such as piezoelectric excitation [ 41 ], Lorentz excitation [ 42 ], magnetic excitation [ 43 , 44 , 45 , 46 ] and thermal excitation [ 47 ].…”

“…Efforts over the last 20 years to further optimize strain sensor readout have resulted in piezoresistive cantilevers that exceed standard optical beam readout in terms of low-noise imaging [ 15 ]. Furthermore, a large number of different applications in the AFM field [ 35 , 37 , 38 , 40 , 50 , 51 , 52 ], but also for other cantilever sensor techniques, such as torque magnetometry [ 53 ] or gas sensors [ 54 ], have been published. Although there is a great potential for the use of self-sensing AFM cantilevers in bio-applications, only very few attempts have been documented to use them in liquid [ 55 ] or for imaging biological samples in liquid [ 56 ].…”

Correlative In-Situ Analysis on the Nanoscale by combination of AFM and SEM

“…It allows direct in-situ combination of these complementary techniques due to the simultaneous operation of SEM and AFM inside the vacuum chamber. [1,2] Therefore, SEM imaging, chemical information by EDX, real 3D topography, phase information, mechanical, electrical, and magnetic properties by AFM can be combined in an easy and interactive way. Furthermore, due to the open design it can be combined with additional add-ons, e.g., tensile stages, nano-indentors [2] or nano-manipulators ( Figure 1a).…”