In-Situ Sem/Fib Nanoindenter

FEMTO TOOLS

IN-SITU SEM/FIB NANOINDENTER

FT-NMT04 NANOMECHANICAL TESTING SYSTEM

Product Brochure FT-NMT04 NANOMECHANICAL TESTING SYSTEM APPLICATION OVERVIEW

The FT-NMT04 Nanomechanical Testing System is a versatile in-situ SEM/FIB nanoindenter capable of accurately quantifying the mechanical behavior of materials at the micro- and nanoscale. As the world’s first MEMS-based in-situ SEM nanoindenter, the FT-NMT04 is based on the patented FemtoTools Micro-Electro-Mechanical System (MEMS) technology. Leveraging over two decades of technological innovations, this in- situ nanoindenter features unmatched resolution, repeatability and dynamic stability. The FT-NMT04 in-situ SEM nanoindenter is optimized for the mechanical testing of metals, ceramics, thin films, as well as microstructures such as meta- materials and MEMS. Furthermore, the FT-NMT04 is modular and can extend its capabilities to accommodate the versatile requirements of various research fields. Typical applications include the quantification of plastic deformation mechanisms by compression testing of micro-pillars or tensile testing of dog-bone shaped specimens, thin films, or nanowires. Furthermore, continuous stiffness measurement (CSM) during bending enables the quantification of the fracture toughness and crack growth events during fracture testing of microcantilevers. With unmatched noise floors down to 500 pN in force (guaranteed real world values) and 50 pm in displacement (guaranteed real world values) and com- paratively large ranges of 200 mN and 20 µm, the Femto-Indenter enables The FT-NMT04 Nanomechanical Test- the comprehensive study of mechanical behavior of materials with an unprec- ing System can be integrated in most edented accuracy and repeatability. SEM/FIB systems.

FEATURES

1 FT-NMT04 NANOMECHANICAL TESTING SYSTEM APPLICATION OVERVIEW

MICRO-PILLAR COMPRESSION

• Determination of critical resolved shear stress (CRSS) of slip systems • Characterization of deformation mechanisms under uniaxial stress • Quantification of ductile damage and strain localization

MICRO-CANTILEVER FRACTURE TESTING

• Determination of sub-micron fracture toughness with continuous J-integral method • Characterization of monotonic and cyclic fracture behavior • Quantification of individual crack initiation and propagation events

NANOINDENTATION

• Determination of hardness and Young’s Modulus in low volumes • Quantification of contact mechanics and dynamic response • Characterization of deformation mechanisms under multiaxial stress

Nanoindentation, compression testing, tensile testing, fracture testing, fatigue testing Quantitative mechanical testing and simultaneous imaging with SEM, EBSD or STEM Patented MEMS-based sensing technology enables highest resolution and repeatability of MICRO-TENSILE TESTING force from 0.5 nN to 200 mN and displacement from 0.05 nm to 21 mm • Determination of yield stress, ultimate tensile stress and elongation to Ability to conduct continuous stiffness measurement (CSM) or fatigue measurements up fracture to 500 Hz without the need for complex, dynamic calibrations • Characterization of fracture modes under monotonic and cyclic loading True displacement-controlled testing, enabling the quantification of fast stress-drops • Quantification of strain localization effect and crack initiation and propa- (optional force-feedback based force-controlled measurements are possible as well) gation events 3, 4, or 5-Axis (x, y, z, rotation, tilt), closed-loop sensor to sample alignment using position encoders on all axes High temperature isothermal testing up to 600°C CORRELATE MECHANICAL TESTING WITH STEM/EBSD Simple determination of the indenter area function and frame compliance Powerful data analysis tool to evaluate measurement results and apply fits or functions • Quantitative study of strain localization to calculate material properties • Quantitative study of phase transformations • Quantitative study of texture evolution SEM image synchronization enabling the matching of the SEM images to the data in the • Quantitative study of dislocation dynamics nanomechanical measurements • Quantitative study of grain boundary migration Compact, modular design enables the integration into almost any SEM Customizable measurement procedures and principles

Overview 2 SYSTEM BUILDUP AND CONFIGURATIONS

The FT-NMT04 can be set up in three different main configurations. Each configuration is specifi- cally designed for a group of applications and offers a unique set of features. Furthermore, by adding or removing the FT-SEM-ROT Rotation Stage or FT-SEM-ROT/TILT Rotation & Tilt Stage, each configuration can be realized with only a few simple steps.

FT-NMT04-XYZ

Key feature • Force sensing range: +/- 200 mN • Force noise floor (10 Hz): 500 pN • Displacement range: 25 µm • Displacement noise floor (10 Hz): 50 pm 1 2 • Continuous stiffness measurement and fatigue testing up to 500 Hz 4 • 3-axis sensor-to-sample alignment 5 • Size: 120 x 44 x 72 mm Key applications 3 • Micro-pillar compression • Micro-cantilever fracture testing • Fatigue testing • Nanoindentation • Micro-tensile testing FT-NMT04-XYZ-R

Additional features compared to FT-NMT04-XYZ • Sample rotation range: 360° • Sample rotation noise floor (10Hz): 35 µ° • Sample revolver with 3 samples 2 • 4-axis sensor-to-sample alignment 1 6 • Size: 134 x 72 x 44 mm 4 Additional applications 5 compared to FT-NMT04-XYZ • EBSD or TKD correlative nanome- 3 chanical testing • STEM correlative nanomechanical SYSTEM COMPONENT LEGEND testing • Nano-tensile testing with the Fem- toTools FT-TT02 Nano-Tensile Test- ing Chip • Faster testing of multiple samples (sample revolver)

3 FT-NMT04 NANOMECHANICAL TESTING SYSTEM 1. Nanoindentation 2. SEM Imaging 3. EBSD Analysis FT-NMT04-XYZ-RT

Force Additional features compared to FT-NMT04-XYZ EBSD EBSD EBSD • Sample tilt range: 90° 200 SEM pole piece 160 • Sample tilt noise floor (10Hz): 35 µ°

120 • Sample rotation range: 180° FT-NMT04 2 Force (mN) 80 6 EBSD • Sample rotation noise floor (10Hz): 40 35 µ° 0 0 400 800 1200 Displacement1 (nm) • Size: 170 x 72 x 44 mm 5 4 7 Additional applications compared to FT-NMT04-XYZ • Sequential nanoindentation and 3 subsequent high resolution SEM imaging • Sequential nanoindentation and subsequent EBSD mapping

FT-NMT04-XYZ-R 1. Nanoindentation 2. SEM Imaging 3. EBSD Analysis

Force

EBSD EBSD EBSD

200 SEM pole piece 160

120 FT-NMT04 Force (mN) 80 EBSD 40

0 0 400 800 1200 Displacement (nm)

SYSTEM COMPONENT LEGEND

1 0ne-axis nanopositioning stage with high-resolution position encoders, enabling movements over a range of 21 mm with 1 nm noise floor 2 Two-axis nanopositioning platform with high-resolution position encoders, enabling movements over a range of 12 x 12 mm with 1 nm noise floor 3 Flexure-based, linear piezo scanner with capacitive position encoders for continuous and fast movement over a range of 25 µm with 0.05 nm noise floor 4 FT-S Microforce Sensing Probe with a force sensing range from 0.5 nN to 200 mN (sold separately) 5 Sample holder 6 Sample rotation stage with rotary encoder for the closed-loop sample rotation with 35 micro-degrees noise floor 7 Sample tilt stage with rotary encoder for the closed-loop sample tilting with 35 micro-degrees noise floor

System Buildup and Configurations 4 MEMS-BASED NANOINDENTATION TECHNOLOGY

1-Axis Microforce Sensing Probe The FT-NMT04 Nanomechanical Testing System is a high-resolution, Micro-Electro-Mechanical Sys- tem (MEMS) based in-situ SEM/FIB nanoindenter. While typical nanoindentation systems feature force sensing technologies based on precision- machined and assembled components, Femto- Tools is using semiconductor fabrication technology to monolithically machine the entire force sensor out of single crystalline silicon wafers. This approach enables the fabrication of much 2-Axis Microforce Sensing Probe smaller structures. The design of load cells with high sensitivity, resolution and repeatability is therefore possible, overcoming the limitations of more traditional technologies. Furthermore, the small size of the MEMS sensing element results in a mass that is orders of magnitude lower than that of load cells using conventional technologies. In combination with the high stiffness of silicon flexures, the FemtoTools FT-S Microforce Sensing Probes provide a high natural 1-Axis Microforce Sensing Probe frequency (up to 50 kHz) and the related ability with integrated tip heater to measure fast events or to conduct fatigue or cyclic tests at higher frequencies. One additional benefit of the compact MEMS-based force sensing technology is the small form factor of the FT- NMT04 (120 mm x 72 mm x 44 mm). This enables the integration of the FT-NMT04 in most SEM / FIB systems.

MEMS-BASED MICROFORCE-SENSING PROBE

5 FT-NMT04 NANOMECHANICAL TESTING SYSTEM Software and Technology 6 APPLICATION EXAMPLES MICRO-PILLAR COMPRESSION

Work conducted by: D, Gianola et al., Gianola Lab, Ma- terials Department, UC Santa Barbara, USA. In-situ SEM micro-pillar compression tests provide a way to measure the uniaxial mechanical response of low 4 volumes of materials and to directly correlate the stress-strain data to in- 3 dividual deformation events. It enables 2 to quantify specific phases and parti- 1 cles or to study size effects, in terms 0 100 Applied force (mN) of deformation behavior and strength- 0 5 10 15 20 80 Deformation (µm) ening mechanisms. In order to resolve 2 individual deformation events, key re- 30 60 4 1.5 quirements for the measurement sys- 40 500 nm 3 tem are high load and displacement 20 1 2 resolution, as well as fast data acquisi- 20 0.5 10 Applied force (µN) 1 tion rate. a b c d 0 After identification of a suitable loca- 0 0 100 Applied force (mN) 0 Applied force (µN) Applied force (mN) −20 10 0 2.5 5 7.5 10 12.5 15 17.5 20 0 5 10 15 20 tion in terms of microstructure or 0 2.5 5 7.5 -0.5 80 Sample deflection (µm) Deformation (µm) crystal orientation using SEM and Deformation (µm) 2 −1 EBSD, micro-pillars are prepared by 0 1 2 3 4 5 6 7 8 30 60 top-down milling with focused-ion 1.5 Sample deflection (µm) 40 20 beam (FIB). Decreasing ion currents 1 20 are used from the machining of the 0.5 10 Applied force (µN) 0 structure to the final surface polishing in order to reduce FIB damage. 0

Applied force (mN) 0

−20 Applied force (µN) 500 nm 0 2.5 5 7.5 10 12.5 15 17.5 20 0 2.5 5 7.5 10 During compression, linear elastic- -0.5 Deformation (µm) ity Sampleis observed deflection in (µm) the initial loading −1 stage, before yielding and plasticity. 1000 0 1 2 3 4 5 6 7 8 Sample deflection (µm) In the plastic regime, a serrated plas- b tic flow behavior with sudden stress 800 c c d drops followed by reloading periods a is often characteristic of dislocation 600 slip events. For example, a correla- 660 unfiltered signal 400 filtered signal tion is shown between stress drops in 640 start of load drop 620 end of load drop the stress-strain data and shear-band 200 600 1000 formation seen in SEM with a) elastic 580 Engineering stress (MPa) 60 b loading, b) nucleation of the first slip 0 560 800 c c d event, c) intersection with top surface 0 5 10 15 20 50 540 Engineering strain (%) Load (MPa) a 520 and d) multiplication of slip events. 40 600 It is worth noting that load-controlled 500 480 660 unfiltered signal testing systems show strain bursts 0.25 0.6 0.9 1.0 1.1 1.2 460 400 640 filtered signal (not stress drops) in the stress–strain mWstart of loadmW dropmW mW mW 6200.20 end of load drop 90 100 110 120 130 140 150 160 170 curve, preventing the quantitative Time (s) 200 6000.15 study of these mechanisms. A key re- 580 Engineering stress (MPa) 60 0.10 0 quirement of the system is therefore 560 0 5 10 15 true20 displacement50 control. In combina- 5400.05 Engineering strain (%) Load (MPa) Elastic limit tion with an ultra-low load noise floor, Engineering strain 520 40 0 the statistical analysis of even smaller 50010.5 magnitude stress drops is possible. 48010.0 0.25 ( µN ) 0.6 0.9 1.0 1.1 1.2 Force 4609.50 mW mW mW mW mW This enables to gain new insight into 500 1000 1500 2000 2500 0.20 90 100 Time110 (s) 120 130 140 150 160 170 the nature of the interactions between Time (s) 0.15 dislocations and various lattice de- X. Zhao, D.J. Strickland, P.M. Derlet, M.R. He, Y.J. Cheng, J. Pu, K. Hattar, and D.S. Gianola. “In 0.10 fects. situ measurements of a homogeneous to heterogeneous transition in the plastic response of 0.05 ion-irradiated ≤111≥ Ni microspecimens.” Acta Materialia, 2015 Elastic limit Engineering strain 0 10.5 10.0 ( µN )

Force 7 FT-NMT04 NANOMECHANICAL TESTING SYSTEM 9.50 500 1000 1500 2000 2500 Time (s) FRACTURE TESTING

Work conducted by: S. Gabel, B. Merle, M. Göken, Department of Materials Sci- ence and Engineering, Institute I, University of Erlangen-Nuremberg, Germany Fracture toughness is a key property in most engineering applications. Frac- a b ture experiments at small scale using micro-cantilever bending tests are crucial to determine fracture toughness in low volumes of materials. Fur- thermore, these tests provide crucial information to quantify the contribution of specific microstructural features to the overall crack resistance of a material. Moreover, in-situ SEM micro- 2 µm 2 µm cantilever bending tests provide new insights into the micromechanisms of fracture by combining the force-dis- c d placement data with direct crack path observations. The typical micro-cantilever bending test uses compression loading of a free-standing notched cantilever beams, prepared with lithography or Focused Ion Beam (FIB). For brittle

fracture, the fracture toughness KIC is determined from the stress intensity factor K at the maximal load. A key re- 2 µm 2 µm I quirement of the measurement system 3500 is true displacement control to avoid 3500 catastrophic failure of specimens once 0.6 3000 0.6 3000 the crack becomes unstable, which is 0.5 2500 typical with force-controlled systems. 0.5 2500 For elastic-plastic fracture, the J-In- 0.4 2000 0.4 2000 tegral method is typically used to ana- 0.3 1500 lyze the crack growth resistance curve 0.3 1500

Force (mN) 0.2 1000 (J-R curve) and elastic-plastic fracture Stiffness (N/m) Force (mN) 0.2 1000 toughness (J ). Generally, higher K , 0.1 500 Stiffness (N/m) IC IC 0.1 500 JIC or steeper J-R curve indicate that a 0.0 0 material is more resistant to fracture. 0.0 0 1 2 3 4 5 6 7 8 0 0 1 2 Displacement3 4 (µm) 5 6 7 8 Micro-cantilever bending testing us- Displacement (µm) ing continuous stiffness measurement (CSM) enables to monitor the evolution

of crack length and compute continu- 1000 1000 ous J-integral from periodic unloading 800 segments, and therefore to build con- 800 tinuous J-R curves. 600 By combining true displacement con- 600 trol, high load and displacement reso- 400 400 lutions, a wide harmonic frequency

8 J-Integral (N/m) 200 range and fast data acquisition rate,

8 J-Integral (N/m) 200 FT-NMT04 enables the precise control 0 of the fracture process and the quan- 0 0.0 0.2 0.4 0.6 0.8 0.0 0.2 Crack growth0.4 ∆a (µm) 0.6 0.8 tification of the effect of individual mi- Crack growth ∆a (µm) crostructural features on the fracture Technique based on: Ast J., Merle B., Durst K., Göken M. “Fracture toughness evaluation of NiAl toughness of materials. single crystals by microcantilevers - A new continuous J-integral method” (2016) Journal of Materials Research, 31 (23), pp. 3786-3794.

Application Examples 8 APPLICATION EXAMPLES NANOINDENTATION

200200

Nanoindentation is a standard and ef- 160160 ficient method to study the mechanical 200 properties of materials at small scale 120120 160 with minimal sample10 preparation. The 10 Force (mN) technique is ideal for the study of thin Force (mN) 8080 120 films or low material volume. In addi- 5 5 tion to hardness and elastic modulus, 4040 Force (mN) 80 nanoindentation gives useful insight 0 0 00 40 into the creep, fracture and fatigue 00 400400 800800 12001200 properties of materials. The multiaxial DisplacementDisplacement (nm) (nm) Relative Error (%) Relative Error (%) 0 -5 -5 0 400 800 1200 stress-field underneath the indenter Displacement (nm) enables the activation of slip systems 5 µm 10 10 in different planes15 and15 200therefore200 400400 com600600 - 800800 1515 200200 400400 600600 800800 prehensive investigationContact of depthcomplex hc (nm) Contact depth hc (nm) 140 Results from 100 indentations plasticity mechanisms. Making use of 140 Results from 100 indentations (complete data set / no outliers are removed) 120 (complete data set / no outliers are removed) size effect in miniaturized samples also 120 enables to study the plastic behavior of 100 quasi- brittle materials. 1.100 Nanoindentation 15 2. SEM Imaging 3. EBSD Analysis 80 By combining ultra-high11 load and dis- 80 60 10 placement resolutions with in-situ 60 SEM observation, FT-NMT04 enables Force40 10 40 9 to measure the mechanical proper- Reduced Modulus (GPa) 20 ties of specific sub-micron-scale mi- Reduced Modulus (GPa) 20 EBSD EBSD EBSD 6 0 Hardness (GPa) crostructural features and to directly 200 0 0 50 100 150 200 250 300 9 0 50 100 150 200 SEM250 pole piece 300 visualize the formation of pile-up, slip 160 Contact depth hc (nm) Hardness (GPa) 120 3 Contact depth hc (nm) FT-NMT04 bands and cracks. Making use of an in- Force (mN) 80 8 150.5 20010 40020 60030 80040 EBSD novative sequential nanoindentation/ 40 20 20 Contact depth hc (nm) 0 Results from 100 indentations EBSD protocol, it also enables to study 018 400 800 1200 Results from 100 indentations 1515 200200 400400 600600 800800 18 Displacement (nm) (complete data set / no outliers are removed) the evolution of strain localizationContact depth and hc (nm) 16 100 (complete data set / no outliers are removed) 16 phase transformation during succes- 14 14 sive indentations. 75 12 12 85 While standard nanoindentation pro- 10 10 vides measurement data72.5 at the onset 8 8 70 of unloading, using Continous Stiffness Hardness (GPa) 6 Hardness (GPa) 64 Measurement (CSM) enables70 to record 4 55 both hardness and elastic modulus as 2 Reduced Modulus (GPa) 20 a function of the indenter67.5 penetration 0 50 100 150 200 250 300 Reduced Modulus (GPa) 0 0 50 10040 150 200 250 300 depth. With high load and displacement 150.5Contact20010 depth40020 hc (nm)60030 80040 ContactContact depth depth hc (nm) hc (nm) resolutions, CSM nanoindentation65 with 1515 200200 400400 600600 800800 FT-NMT04 enables to quantifyContact the depth hc (nm) 1. Nanoindentation 2. SEM Imaging 3. EBSD Analysis evolution of the mechanical response from shallow penetration depths and

the onset of plasticity, to the bulk Force material. Furthermore, the extended harmonic frequency range of the FT- EBSD EBSD EBSD NMT04 system (up to 500 Hz with very 200 SEM pole piece little contribution from the measure- 160 120 FT-NMT04 ment system), combined with a fast Force (mN) 80 EBSD data acquisition rate, will enable the 40

0 0 400 800 1200 unprecedented quantitative dynamic Displacement (nm) mechanical analysis of the viscoelastic and viscoplastic behavior of materials.

9 FT-NMT04 NANOMECHANICAL TESTING SYSTEM MICRO-TENSILE TESTING

Work conducted by: J. L. Wardini, T. Rupert, Ru- pert Lab, University of California Irvine, USA Large scale tensile testing is a com- monly used test to quantify the elastic a b modulus, yield-, ultimate-, and fracture-strength of materials. However, while these tests provide valuable insights into the overall material properties, they average out the effects of constituents such as individual phases and interfaces. To quantify the properties of a single phase or interface, micro-tensile test- 10 µm 10 µm ing is required, as shown in the image sequence on the left. Furthermore, by scaling down these experiments c d even more, single plastic deformation mechanisms can be detected and in- vestigated. For sample preparation, focused-ion beam (FIB) can be used to create dog- bone shaped samples with a uniform cross-section that remain attached to the original substrate. FIB can also be used to machine a gripper shape into 1.5 the tip of the force-sensing probe. This 10 µm start25 of µmplastic event end of plastic event gripper shape enables the interlocking 1.0 with the dog bone sample in order to 0.5 conduct micro-tensile tests.

) During tensile loading, linear elastic-

µN 0.0 ity is observed in the initial stage, be- -0.5 fore yielding, plasticity and, eventually,

Force ( fracture. -1.0 A critical testing requirement to measure the full stress-strain curve is 1.5 0 2 4 6 true displacement-controlled testing, Displacement (nm) which prevents catastrophic failure of the specimen during unstable crack 10 µm propagation. As a result, the material’s behavior after the ultimate strength (with decreasing slope of the stress- 1.2 strain curve) can be characterized. 1.1 By combining this micro-tensile testing method with the deposition of speck- 0.8 les or line markers (shown on the left) 0.6 along the sample, digital image corre- 0.4 lation (DIC) can also be used to obtain the local strain along the loading axis. 0.2 Local strain Global strain Engineering stress (GPa) 0.0

10 µm 10 µm 0.0 0.1 0.2 0.3 Engineering strain

Z. Fu, L. Jiang, J. L. Wardini, B. E. MacDonald, H. Wen, W. Xiong, D. Zhang, Y. Zhou, T. J. Rupert, W. Chen, E. J. Lavernia, “A high-entropy alloy with hierarchical nanoprecipitatesand ultrahigh strength.” Science Advances, 2018

Application Examples 10 APPLICATION EXAMPLES FATIGUE TESTING

Work conducted by: S. Singh, A.S. Singaravelu, and N. Chawla, Cent- er for 4D Materials Science, Arizona State University, USA In-situ micro-fatigue testing enables the quantitative study of fatigue crack initiation and propagation events, with direct crack path observations and continuous monitoring of the dynamic mechanical response. It provides unprecedented insights into fatigue micro-mechanisms and their influence on the fatigue life of materials and complex structures, such as nano-composites and laminates. 10 µm With its wide dynamic range (without system resonance), fast data acquisition rate and true displacement control, the FT-NMT04 enables low- and high-cycle in-situ fatigue testing up to 500 Hz and more than 5 million load cy- cles in less than 3 hours. A typical experimental set-up consists in the cyclic bending of a microcanti- lever. Other possibilities include cyclic compression of micropillars or cyclic tensile and compression testing of tensile sample such as e.g. thin lamellae. 5 µm Cyclic loading is then applied on the specimen. The test is interrupted at regular intervals for high-resolution SEM imaging, in order to observe in- dications of crack initiation, propagation, deflection at interfaces or surface damage. The dynamic stiffness response of the specimen is monitored to provide crucial insights, into e.g. short or long crack initiation and growth, or cyclic hardening and softening mechanisms. 5 µm In addition, correlative EBSD mapping enables to follow strain accumulation ahead of the crack tip and its link with subsequent crack propagation along critical planes. The fatigue life can be evaluated with changes in the specimen’s stiffness. The data can then be compared to observations of fracture surfaces after final failure.

200 nm

S. Singh, A.S. Singaravelu, and N. Chawla, “Deformation Behavior of Co-Sputtered and Nanolami- nated Metal/Ceramic Composites” Dissertation for the Doctor of Philosophy Degree, Center for 4D Materials Science, Arizona State University, 2018

11 FT-NMT04 NANOMECHANICAL TESTING SYSTEM CORRELATIVE STEM /EBSD IN SEM

Work conducted by: D, Gianola et al., Gianola Lab, Ma- terials Department, UC Santa Barbara, USA. The FT-NMT04 is specially-designed to combine the study of the stress-strain response of materials not only with the observation of surface events, but also with EBSD, TKD and STEM characterization to gain unprecedented quantitative insight into phase transformation and dislocation dynamics. Micro-tensile testing, pillar compression and cantilever bending in correlation with EBSD enable to monitor and 50 µm 5 µm quantify dynamic phase transformations and strain localization. To further explore plasticity at the dislocation scale, micro-tensile testing of electron-transparent specimens and thin films can be performed in correlation with TKD and STEM detectors. After selecting a proper location in terms of microstructure and crystal orientation using SEM and EBSD, a specimen is extracted by focused-ion beam (FIB) machining. It is then placed 5 µm on a testing sample support, such as the FemtoTools Nano-Tensile Testing Chip, and secured using ion (or electron) beam induced deposition. FIB carving and thinning of the micro-tensile specimen down to electron trans- parency is then performed with low voltage to minimize FIB damage and enable for STEM imaging. During loading, linear elasticity is observed first, before a plastic regime characterized by multiple load drop events and the final fracture of the 1 µm specimen. With true displacement control, fast 1.5 data acquisition rate and ultra-high start of plastic event end of plastic event load and displacement resolution, the 1.0 analysis of the amplitude and time of 0.5 individual load drops is possible. In

) correlation with STEM images, it pro-

µN 0.0 vides the characteristic load (down to -0.5 less than 0.5 µN) attributed to specific

Force ( plastic events. It gives the unique op- -1.0 portunity to study distinct dislocation interactions with lattice defects, such 1.5 500 nm 0 2 4 6 as Orowan bowing or shearing of pre- Displacement (nm) cipitates by partial or full dislocation J. C. Stinville, E. R.Yao, P. G. Callahan, J. Shin, F. Wang, M. P. Echlin, T. M. Pollock, D. S.Gianola, pairs. It enables to build a statistical “Dislocation Dynamics in a Nickel-Based Superalloy via In-Situ Transmission Scanning Electron understanding of plastic localization Microscopy.” Acta Materialia, 2019 mechanisms down to the dislocation scale. 1.2 1.1 Application Examples 12 0.8 0.6 0.4 0.2 Local strain Global strain Engineering stress (GPa) 0.0

0.0 0.1 0.2 0.3 Engineering strain 4 3 2 1 0 100 Applied force (mN) 0 5 10 15 20 80 Deformation (µm) 2 30 60 1.5 40 20 1 20 0.5 10 Applied force (µN) 0 0

Applied force (mN) 0

−20 Applied force (µN) 0 2.5 5 7.5 10 12.5 15 17.5 20 0 2.5 5 7.5 10 -0.5 Deformation (µm) Sample deflection (µm) −1 30 0 1 2 3 4 5 6 7 8 without thermal treatment Sample deflection (µm) APPLICATION EXAMPLES with thermal treatment 20 MICROSTRUCTURE TESTING 10 b Applied force (mN) a c THERMOMECHANICAL CREEP TESTING OF INDIVIDUAL METALLIC GLASS NANOWIRES 0 Metallic glasses are receiving growing 0 2.5 10 15 20 attention due to their unique mechani- Deformation (µm) L =1.8 µm cal properties such as a large elastic 0 1000 limit and high fracture toughness. Fur- b 800 c d/e thermore, the large supercooled liquid a region enables superplastic forming, 600 opening up new material processing Pt-EBID 80 20 strategies. Therefore, a quantitative 400FT-S Microforce understanding of their thermomechan- Sesning Probe tip 60 60 15 200 ical behavior is crucial. The depicted I cantilever 1 50 40 10 work from Prof. Daniel S. Gianola at UC 1 µm Engineering stress (MPa) cantilever 2 0 Santa Barbara investigates the super- 0 0.05 0.1 0.15 0.2 40 20 5 Engineering strain plastic-like flow of metallic glass. For 30 0 0 0.25 0.6 0.9 1.0 1.1 1.2 Actuation f orce ( µ N )

this purpose a metallic glass nanowire ∆ L Sample deflection (µm) mW mW mW mW mW 20 -20 is attached between the FT-S Micro- 0.20 0 0.5 1 1.5 2 2.5 force Sensing Probe and a second sub- 0.15 10 Time (s)

strate by Pt-EBID. While performing a Output voltage change (mV) 0.10 0 80 creep test (applying a20 constant tensile 0 20 40 60 80 100 0.05 Applied force (µN) 60 load while measuring the deformation), 15 Elastic limit Engineering strain 40 the temperature is increased10 stepwise 0 by passing an electric current through 10.52 20 5 10.0 ( µN )

the nanowire. With this method, the Force 1.5 0 0 1 µm 9.50 500 1000 1500 2000 2500 creep behavior is analyzed at different Time (s) Actuation f orce ( µ N ) -20 1 0 0.1 nanowire0.2 0.3 temperatures.0.4 4 0.5 Sample deflection (µm) Time (s) 3 0.5 80 40 STABLE COMPRESSION2 TESTING OF MICROSCAFFOLDS0 60 30 Applied force (µN) Microscaffolds are1 used40 in various are- 20 -0.5 as such as in materials0 science for the 100 Applied force (mN) 20 10 −1 creation of ultra-light0 materials5 10 or in 15 20 0 1 2 3 4 5 6 7 8 0 0 80 biology as a cellular environmentDeformation with (µm) Sample deflection (µm)

Applied Voltage (V) 2 Actuation f orce ( µ N ) -20 0 0.1 0.2 0.3 0.4 0.5 a predefined mechanical30 rigidity, used 60 for the growth of artificial tissues.Time (s) 100 1.5 40 Compression testing20 of scaffolds ena- 80 1 2 bles the determination of their elastic 20 60 0.5 10 Applied force (µN) and plastic behavior even beyond the 0 collapsing point. Image1 courtesy: ETH 40 0

Applied force (mN) 0

−20 Applied force (µN) 0 2.5 5 7.5 10 12.5 15 17.5 20 Zurich, Switzerland0 2.5 5 7.5 10 2 µm 20 -0.5 0 Deformation (µm) Sample deflection (µm) Applied force (µN) 0 −1 30Applied force (µN) 0 1 2 3 4 5 6 7 8 −1 without thermal treatment Sample deflection (µm) 0 1 2 3 4 5 6 7 8 −20 IN- AND OUT-OF-PLANEwith thermalMECHANICAL treatment TESTING OF MEMS0 2.5 /5 NEMS7.5 10 12.5 15 17.5 20 Sample deflection (µm) Sample deflection (µm) The continuous miniaturization20 trend has been driving the typical feature size of MEMS towards the nanoscale. 10 80 20 As a result, conventional mechanical b testing principlesApplied force (mN) baseda on optical mi- c 60 15 croscopy have reached their limit. Due 40 10 0 to the higher resolution0 imaging2.5 capa10- 15 20 20 5 100 bilities of SEMs, in-situ SEM mechanicalDeformation (µm) testing enables direct1000 quantification 0 0

80 Actuation f orce ( µ N )

of mechanical and electro-mechanicalb Sample deflection (µm) 60 800 c d/e -20 0 0.5 1 1.5 2 2.5 40 properties of MEMS / NEMS.a 5 µm Time (s) 20 600 0 80 20 Applied force (µN) 400 −20 0 20 40 60 80 10013120 140 160 FT-NMT04 NANOMECHANICAL TESTING SYSTEM 60 60 15 Sample deflection (µm) 200 cantilever 1 50 40 10 Engineering stress (MPa) cantilever 2 0 0 0.05 0.1 0.15 0.2 40 20 5 Engineering strain 30 0 0 0.25 0.6 0.9 1.0 1.1 1.2 Actuation f orce ( µ N ) Sample deflection (µm) mW mW mW mW mW 20 -20 0.20 0 0.5 1 1.5 2 2.5 0.15 10 Time (s) Output voltage change (mV) 0.10 0 0 20 40 60 80 100 0.05 Applied force (µN) Elastic limit Engineering strain 0 10.5 10.0 ( µN ) Force 9.50 500 1000 1500 2000 2500 Time (s) ACCESSORIES

FT-S MICROFORCE SENSING PROBES The FemtoTools FT-S Microforce Sens- ing Probes are sensors capable of measuring forces from sub-nanone- wtons to 200 millinewtons along the sensor’s probe axis. Both compression and tension forces can be measured. Single SI-traceable pre-calibration for each probe in combination with an out- standing long-term stability guaran- tees significantly higher measurement accuracy than other force sensing systems in this force range. Special- ized versions are also available, includ- Model Range Noise floor (10 Hz) ing 2-Axis Microforce Sensing Probes or Tip Heating. FT-S200 +/- 200 µN 0.5 nN The FT-S Microforce Sensing Probes FT-S2’000 +/- 2’000 µN 5 nN are available with a wide variety of tip materials and geometries including FT-S20’000 +/- 20’000 µN 50 nN diamond Berkovich, cube corner, flat FT-S200’000 +/- 200’000 µN 500 nN punch, wedge, conical and more. FT-S20’000-2Axis +/- 20’000 µN 100 nN +/- 20’000 µN 100 nN

HIGH TEMPERATURE TESTING MODULE The FT-NMT04 can be upgraded with the FT-SEM-HT04 In-situ SEM High Temperature Module. This module enables heating specimens up to 600°C. It is used in combination with the Micro- force Sensing Probe with integrated tip heater, which provides localized heating of the tip to match the temperature of specimens. This module allows for all of the FT-NMT04 capabilities at temperatures up to 600°C, including: high-resolution and high-repeatability nanoindentation, micro-pillar compression, micro-tensile testing and micro-cantilever fracture testing. The In-situ SEM High Temperature Module enables the quantitative study not only of changes in local materials properties, but also of plastic deformation, softening and fracture mechanisms at high temperature. Typical studies include the evolution of hardness, elastic modulus, fracture toughness or activation energy of nucleation of dislocations with temperature.

Application Examples 14 §

ACCESSORIES

SCRATCH TESTING MODULE The FT-NMT04 can be upgraded with the FT-SEM-ST04 In-situ SEM Scratch Testing Module to allow for nano- scratch, nano-wear and nano-friction testing, as well as scanning probe microscopy (SPM) imaging. The diamond tip of a 2-Axis Microforce Sens- ing Probe is pushed across the sample surface while applying a ramping or constant normal load at a given speed. Scratch testing yields quantitative insights into various properties such as failure mechanisms at the nanoscale, thin film adhesion, friction coefficients and scratch or wear resistance of ma- 4 terials. Furthermore, high-resolution SPM imaging can be used for topogra- 2 Normal Force (mN) phy imaging before and after scratch, 0 wear or nanoindentation testing. It 4 provides direct visualization of pre- test surface roughness and post-test 2

surface deformation or damage. Lateral Force (mN) 0 Combining a 20 x 20 x 25 µm imaging 150 200 5 400 10 600 15800 20 range with a 50 pm scanning noise Position (µm) floor, this module is coupled to the 2-Axis Microforce Sensing Probes fea- turing a 100 nN noise floor for a 20 mN force range. In addition, the module benefits from a long-range probe po- sitioning noise floor of 1 nm to target 4 0 specific testing or scanning locations. Adding to the technical superiority 2 -100 Normal Force (mN) of the FT-NMT04 for high-resolution, 0 high-repeatability nanoindentation, 4 -200 the Scratch Testing Module enables Profile (nm) the comprehensive study of materials 2 -300

properties at surfaces and interfaces, Lateral Force (mN) 0 15 200 400 600 800 -400 as well as the quantitative characteri- 0 5 10 15 20 150 200 5 400 10 600 15800 20 Position (µm) Position (µm) zation of elasto-plastic deformation 4 and fracture mechanisms at the nanoscale. Typical examples include the 2 Normal Force (mN) characterization of critical loads for 0 cohesive and adhesive failures, the ef- 4 fect of surface roughness on shallow indents or the impact of near-surface 2 0 plasticity on friction. Lateral Force (mN) 0 150 200 5 400 10 600 15800 20 -100 Position (µm)

-200 Profile (nm) -300

-400 150 200 5 400 10 600 15800 20 Position (µm) 0

-100 15 FT-NMT04 NANOMECHANICAL TESTING SYSTEM -200 Profile (nm) -300

-400 150 200 5 400 10 600 15800 20 4 Position (µm)

2 Normal Force (mN) 0 4

Lateral Force (mN) 0 150 200 5 400 10 600 15800 20 Position (µm)

-100

-200 Profile (nm) -300

-400 150 200 5 400 10 600 15800 20 Position (µm) FT-SEM-ROT ROTATION STAGE FT-NMT04-XYZ can be upgraded with a rotation stage. This enables: • Rotary alignment of the sample to the indenter tip • Testing of multiple samples in one session by using the rotation stage as a sample revolver • Together with the included sensor and sample extender, the rotation stage can be used to enable correlative nanomechanical testing and STEM, TKD or EBSD imaging. In the case of TKD and STEM, the use of a specialized sample holder such as the FemtoTools FT-TT02 Nano-Tensile Testing Chip is re- currently not available in USA, Japan and Germany quired. FT-SEM-ROT/TILT ROTATION & TILT STAGE

With only a few simple steps, the FT- NMT04-XYZ can be upgraded with a rotation/tilt stage. This enables the sequential alignment of the sample towards the nanoinde- ter, the SEM’s pole piece and the EBSD detector. With this functionality, the exact shape of nanoindents as well as the strain fields around the indent can be evaluated.

currently not available in USA, Japan and Germany FT-TT02 NANO-TENSILE TESTING CHIP The FT-TT02 Nano-Tensile Testing Chip Sample preparation with FIB enables the tensile testing of small, SEM thin samples while imagine with STEM or TKD. This MEMS-based Tensile Test- ing Chip consist of a movable body that FT-NMT04 FT-TT02 is suspended by four flexures within XYZ-R an outer, fixed frame. The sample that STEM needs to be tested, such as a thin metallic samples, can be placed over the gap between the movable and the fixed part of this chip. The sample can be FT-TT02 FT-TT02 - Integrate the sample fixed with either focused ion beam dep- with FIB-deposition osition (IBID) or electron beam induced deposition (EBID). For the tensile testing, the force is applied to the movable part of the Tensile Testing Chip by a FT-S Microforce Sensing Probe with a hook shaped tip, mounted on the FT- NMT04 Nanomechanical Testing Sys- tem.

Accesories 16 TECHNICAL SPECIFICATIONS FT-NMT04-XYZ NANOMECHANICAL TESTING SYSTEM

Number of axes (coarse) 3 Actuation principle (coarse) Piezoelectric stick slip XYZ actuation range (coarse) 21 mm x 12 mm x 12 mm 72 mm Min. motion increm. (coarse) 1 nm

Encoder noise floor (10 Hz) 1 nm 120 mm Actuation principle (fine) Piezoelectric scanning Actuation range (fine) 25 µm 33 mm

Min. motion increm. (fine) 0.05 nm 44 mm Encoder noise floor (10 Hz) 0.05 nm Digital resolution (10 Hz) 0.05 pm Position measurement range 0.05 nm - 21 mm Maximum force range*1) ± 200 mN Force noise floor (10 Hz)*2) 0.5 nN *1) Using a FT-S200’000 Microforce Sensing Probe Digital resolution (10 Hz)*2) 0.5 pN *2) Using a FT-S200 Microforce Sensing Probe

FT-NMT04-XYZ-R NANOMECHANICAL TESTING SYSTEM

Additional specifications compared to the FT-NMT04-XYZ Configuration for sample revolver Number of axes (coarse) 4 Sample rotation range 360 ° Rotation noise floor (10 Hz) 35 µ° 72 mm

134 mm 33 mm 44 mm

Configuration for correlative mechanical testing and EBSD/STEM imaging 72 mm

52 mm 170 mm 42 mm 44 mm

17 FT-NMT04 NANOMECHANICAL TESTING SYSTEM FT-NMT04-XYZ-RT NANOMECHANICAL TESTING SYSTEM

Additional specifications compared to the FT-NMT04-XYZ Number of axes (coarse) 5 Sample rotation range 180 ° 72 mm Rotation noise floor (10 Hz) 35 µ°

Sample tilt range 90 ° 170 mm Tilt noise floor (10 Hz) 35 µ° 33 mm 44 mm

Technical Specifications 18 FEMTO TOOLS

FemtoTools AG Furtbachstrasse 4 8107 Buchs / ZH Switzerland

T +41 44 844 44 25 F +41 44 844 44 27

[email protected] www.femtotools.com