AFM-in-SEM
a Cu(100) substrate whose magnetic properties can be selectively changed when irradiated by an ion beam (direct FIB writing). Tis material has the potential for magnetic pat- terning as it is paramagnetic (fcc) at room temperature but can be trans- formed by FIB irradiation into a fer- romagnetic material (bcc) [14]. To identify the ion dose intensity caus- ing the fcc-bcc material transforma- tion, an array of FIB milled squares was prepared, as depicted in Figure 4a. Te change in material crys- tallography is detailed in the SEM image in Figure 4b (ion dose intensity of 4.8 × 1015
ions/cm2 ). Simultane- Figure 4: Metastable Fe78 Ni22 thin film on Cu(100) substrate. (a) An array of FIB-milled squares (5 × 5 μm each)
prepared using different ion dose intensities. The highlighted area shows the partial material crystallography trans- formation detailed in the SEM image and corresponding AFM topography (b), and combined 3D CPEM view (c) with a topographical step between the high and low magnetic moment.
steel alloy consists of two phases that are only partially depen- dent on morphology. Te SEM images show only the edges of the grains, but information about grain topography is miss- ing. Simultaneously acquired AFM images provide data of the true surface topography. Te scalable 3D CPEM view combines crystallographic contrast and surface morphology, enabling easier interpretation of the surface with high resolution in all three dimensions. Information about topography enables pre- cise measurement of the height and depth of surface structures as well as estimation of the sample roughness.
In situ Sub-Nanometer Profiling and 3D Topography AFM-in-SEM technology facilitates precise measurement
of height and depth of surface structures in SEM applications. It can be operated in a tilted position up to 60°, which makes it compatible with a FIB and gas injection system. Tis technique is used for surface polishing, sputtering, etching, depositing, or patterning. Te results can be immediately viewed by SEM, however, the detailed information about the surface morphol- ogy of sputtered or deposited material requires AFM analysis, typically ex situ. Te AFM integrated into the FIB-SEM system provides a fast and accurate in situ analysis of the modified surface without the need for sample transfer to another instru- ment and without changing the environment and breaking the vacuum. Tus, the AFM-in-SEM system in combination with CPEM facilitates FIB process optimization. Applications for FIB surface modification are depicted in thin film grown on
Figure 4, which shows a metastable Fe78 2020 May •
www.microscopy-today.com
Ni22
ous measurement of AFM and SEM signals revealed that the crystallog- raphy transformation was accom- panied by a topography change with the step between low and high mag- netic moment approximately 470 pm, as shown in the height profile in Figure 4c. Additionally, the in situ AFM-in-SEM arrangement was cru- cial in this study since the Fe78
Ni22
represents a sensitive sample where the sample surface is prone to imme- diate oxidation upon air exposure.
Measurement of Mechanical Properties Mechanical properties of a material describe its behav-
ior under loading, and LiteScope offers a variety of methods for measurement of mechanical properties (Table 1). Te most studied mechanical properties are stiffness, elasticity, and hardness [15]. Te knowledge of these properties is crucial for design, modeling, and analysis of mechanical systems as well as for applications in life sciences. Te analysis of mechani- cal properties on a nanometer scale by multiple techniques provides information about the texture, crystallography, mor- phology, and properties of individual components and helps to understand the behavior of these systems in the macro- scopic world. A two-component polymer sample, containing polysty-
rene (PS) and low-density polyethylene (LDPE), was used to demonstrate some capabilities for estimation of mechani- cal properties; for this purpose, LiteScope is showcased as a stand-alone AFM. Figure 5a shows the topography of the surface with circular regions embedded into a matrix, which can be well correlated with the sample mechanical proper- ties acquired by energy dissipation, FMM, and force-distance curves (Figure 5c). Energy dissipation and FMM provides qualitative information, and both techniques clearly showed a difference in stiffness between the harder PS matrix and the soſter, embedded LDPE regions. In general, energy dissipation information is read from the drive signal amplitude in tapping mode and is useful as an alternative to FMM, which uses con- tact mode AFM. Tus, the application is suitable for samples
43
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84
