PeakForce Tapping and ScanAsyst An introduction to the technique featuring Bruker s Dimension Edge. Bede Pittenger, Ph.D.

Transcription

1 PeakForce Tapping and ScanAsyst An introduction to the technique featuring Bruker s Dimension Edge Bede Pittenger, Ph.D.

2 Dimension Edge with ScanAsyst: High performance AFM breaking down cost and productivity barriers. Epitaxial growth pattern Best Value Closed-Loop Dimension AFM Solutions for All Applications on Any Sample Highest Productivity for Any User 6/3/2013 2

3 Introduction to AFM: Nearly any phenomenon can be confined to the NanoScale Atoms and molecules can be visualized no diffraction limit. Physical Interaction enables direct nano-mechanical 3-D metrology. Electrically connecting to the tip optionally provides: Work Function, Conductance, Capacitance, and Doping maps. 6/3/2013

4 TappingMode AFM: Bruker s gold standard that changed the world of AFM Tapping Mode 8.5µm Oscillating the probe avoids destructive lateral forces TappingMode PhaseImaging provides high-resolution data, but is unable to assign contrast to a specific property of the sample 6/3/2013 4

5 PeakForce Tapping: Direct force control, wide control range, and high resolution Feedback Controlled Interaction Force Peak Force Control Range pn ~ µn T Sinusoidal ramping at sub-resonance frequencies Retains accurate Z positioning, even at ramp rates ~2kHz Avoids resonances of cantilever to avoid filtering effect Real feedback loop force control Force control benefits from the results of prior force curves Best force control, highest resolution, and greatest stability 6/3/2013 5

6 PeakForce Tapping: New information through identification of nanomechanical properties 1 µm Unlike TappingMode PhaseImaging, PFT can separate nanomechanical information Adhesion image (top left) clearly shows lower adhesion of one component of this polymer composite 6/3/2013 6

7 ScanAsyst and PeakForce Tapping: Combining high performance and ease-of-use PeakForce Tapping is the technology behind these new imaging modes As the probe scans across the sample, we precisely control the peak interaction force between probe and sample Peak Force <100 pn, (lower than TappingMode in most cases) The peak force of each of these curves is monitored and used as the feedback signal Silicon Nitride Cantilever Probes Improves lateral resolution of imaging with 5nm radius Peak Force Tapping Technology Automated Image & Optimization = Technology 6/3/2013 7

8 ScanAsyst: Retaining consistent high-resolution Automatic image optimization results in faster, more consistent results, regardless of user skill level Direct force control at ultralow forces helps protect delicate samples and tips from damage 500nm Elimination of cantilever tuning, setpoint adjustment, and gain optimization makes both air and fluid imaging simple 6/3/2013 8

9 Advanced Capabilities for Everybody: Intuitive workflow & fast access to help guarantee optimized results, every time Scan 6/3/2013 9

10 ScanAsyst and PeakForce Tapping: Enabling optional advanced user control Parameters are pre-set by the experiment workspace but can be change by the user. ScanAsyst constantly optimizes the PeakForce Tapping parameters during imaging Advanced user can switch to manual and fully obtain control of the imaging process 6/3/

11 Polymer Brushes imaged using ScanAsyst: High performance regardless of user level 250nm 25nm (Sample courtesy S. Sheiko, University of North Carolina, Chapel Hill) PBA Polymer brushes are end-tethered polymer chains with backbone and short brushes Applications use their ability to regulate interaction forces between the brush and its environment Automatic image optimization results in consistent high-resolution results 6/3/

12 Alkane chains: Molecular resolution without user interaction C 60 H nm 6/3/

13 Advanced Electrochemistry: Enabling Lithium Ion battery research Complete solution Productive, solvent-compatible EC cell Turnkey 1ppm environmental control Easiest available fluid imaging Enabled by ScanAsyst Critical element for enabling EC research Unambiguous material contrast Enabled by PeakForce Tapping Qualitative adhesion data Height E.g. for SEI layer studies Adhesion SEI Layer Growth 6/3/

14 Lithium battery research Celgard PP membrane 2.5µm 250nm Separator membrane for EV and disposable lithium batteries PeakForce Tapping s direct force control results in high resolution without sample damage or tip contamination 6/3/

15 Thin Layer Structure of OLED Stack: ScanAsyst to analyze surface morphology electronicdesign.com 250nm Morphology and electronic properties of organic semiconductors like ITO are strongly related Microstructure affects OLED current density and luminance. ScanAsyst produces high resolution, quantitative structural information needed to analyze this relationship 6/3/

16 Sapphire Substrates for HB LEDs: Automated parameter adjustment for consistent results Sample chuck holding 9* 2 wafers shown 5µm Patterned sapphire substrates (PSS) have a dense pattern of micron-scale bumps For uniform LED performance, bumps must all match design parameters Optical techniques do not have the spatial resolution necessary 6/3/

17 Imaging of difficult geometries: Direct force control avoids feedback instabilities 65nm 10nm Deep and narrow trenches are difficult to image using Tapping Mode due to excessive damping of probe oscillation Direct force control of ScanAsyst avoids this problem and produces accurate profiles even at the bottom 6/3/

18 Plasmid and Origami DNA in fluids: Automated, consistent, high-resolution results 100nm 100nm Imaging DNA enables studies of DNA-Protein interactions Origami DNA is used to build 3D nanostructures ScanAsyst eliminates cantilever tuning, setpoint adjustment, and feedback optimization for simple imaging in fluids 6/3/

19 Lithium-alumosilicate Glass-Ceramic: Monitoring dynamics of surface change using adhesion Stable platform enables long term studies White: high adhesion Dark: low adhesion Time PFT enables the understanding of dynamics of surface changes 2µm Sample courtesy of: E. Rädlein and U. Brokmann, Institute of Materials Engineering Ilmenau University of Technology (Germany) 6/3/

20 Advanced Nanoscale Capabilities for Beginners and Experts TappingMode MFM Darklift SCM Dimension Edge can produce high resolution maps of many properties Experiment selector quickly and easily opens up many possibilities for AFM measurements 6/3/

21 The Ideal Imaging Mode: Consistent high-resolution imaging Easiest imaging in both air and fluid Unambiguous material contrast Now available on the Dimension Edge 6/3/