basic principles of advanced afm modes & applicationsmodes ... › data › media › files ›...
TRANSCRIPT
Development
Basic Principles of Advanced AFM
Modes & ApplicationsModes & Applications
Dr. Stanislav Leesment, NT-MDT,16th June 2014
Webinar Overview
• AFM Operation: main principles• Topography in Contact and Noncontact modes• Phase Imaging• High Resolution• Choice of cantilever• Spreading resistance imaging (conductive AFM/Current mapping)• Kelvin Probe Microscopy (KPM)• Piezoresponce Force Microscopy (PFM)
M ti F Mi (MFM)• Magnetic Force Microscopy (MFM)• Nanolithography• Force Spectroscopy• HybriD™ Mode• HybriD™ Mode• Questions and Answers
AFM Operation: Main Principles
AFM: Scanning by Sample
SAMPLE SCANNING
AFM: Scanning by Tip
TIP SCANNING
Topography ImagingTopography Imaging. Contact and Noncontact Modes.
Contact Mode
According the Hook’s lawAccording the Hook’s law, Force interaction between tip and the sample isand the sample is proportional to tip bending and the cantilever stiffness. Stiffness for contact mode cantilevers can vary from 0 01 to several N/m0,01 to several N/m
Contact-Mode Based Modes
Noncontact (Semicontact, Tapping, AM-AFM) ModeAFM b 50 kH k 0 5 N/AFM probe, w=50 kHz, k = 0.5 N/m, Q = 80, Rt =10 nm, A0 = 5 nm
S. Belikov et al Fall 2012 MRS Proceedings, 2013
Phase Imaging
Phase Imaging. Scan Examples.
Name: Water on MicaEnvironment: AirTip: NSG10Size: 10x10 umSample and Image Courtesy:Sample and Image Courtesy:Reinier Oropesa-Nuñez, CEAC, Cienfuegos, Cuba
High-Resolution Imaging in AM-AFM in Air
C18H38Phase
C36H74PTFEPhaseHeight
CnH2n+2
C18H38C22H46
2.8 nm3.0 nm
18
22 46C36H74C60H122C122H246C242H486
4.5 nm7.5 nm15.0 nm29.0 nm
18 nm 50 nm 90 nm
Height Height HeightHeightC122H246 C242H486 C390H782 C122H246
C390H782
242 48649.0 nm
135 nm
Image Courtesy: Dr. S. Magonov, NT-MDT
4 of 35750 nm 750 nm550 nm
Magonov, NT MDT Development Co.
Tip Sharpness Limitation
ZAFM line profile
X2
5 10Probe tip
R 10 R=10 nm
R = 1 R 1 nm X axis direction
Real object (e g DNA molecule)Real object (e.g. DNA molecule)
Probes for High Resolution
Left: high-resolution AFM phase image of poly(dG)–poly(dG)–poly(dC) triplex DNA. The top graph shows a cross-section of the image along the white line (at the bottom part of the image). Right: histogram of distances between adjacent peaks on cross-sections taken on many molecules (overall >200 values); the average distance is 3.4 nm (SD = 0.9 nm)
D. Klinov, B. Dwir, E. Kapon, N. Borovok, T. Molotsky and A. Kotlyar. High-resolution atomic force microscopy of duplex and triplex DNA molecules. Nanotechnology 18 (2007), 225102.
Cantilever Choice
Cantilever Choice
NT‐MDT AFM probes
Semicontact / noncontact Contact
HA NC HA HR HA FMHA_C
Semicontact / noncontact(tapping)
Contact
HA_NC, HA_HR, HA_FM
NSG01, NSG10, NSG30, NSG03CSG01, CSG10,
CSG30
Pt TiN A W MFM LM
Conductive Magnetic
Pt TiN Au W MFM01, MFM10
MFM_LM
MFM_HC
Electromagnetic Properties
Spreading Resistance Imaging (SRI)
Spreading Resistance imaging
MDMO‐PPV and PCBM Blend
Top left topography obtained in SSRM mode (-5V), top right – current mapping, bottom right current cross-section profilecross section profile.
MDMO‐PPV and PCBM Blend
Current maps with various bias voltage,
10 V 5 V 1 V-10 V -5 V -1 V
+1 V +5 V +10 V
Conductivity Map of OTS Sample
CurrentTopography
Current contrast of “Flowers” about 2 pA
Sample Courtesy: Prof. Jacob Sagiv, Weizmann Institute of Science, Israel
Probes for Spreading Resistance
Probes for Spreading Resistance should normally have relatively small
20 nm
should normally have relatively small spring constant 0,05 – 1 N/m contact probes and good conductive coating p g g(PtIr, TiN, Au)
Kelvin Probe Force Microscopy (KPFM)
Two-Pass KPFM
KPFM on Carbon Nanotubes
3 3
2 2
1 1
It should be noticed that SKM image reveals three kinds of nanotubes : 1) Nanotubes with electric potential about 1 V, these nanotubes have smallest diameter (about 1.5 nm)
Topography SKM image
) p , ( )2) Nanotubes with electric potential about 0.5 V which have diameter about 2-3 nm 3) Thickest nanotubes which give smallest contrast in SKM and have biggest diameter (4 nm)
Charge Lithography on GaAs
Raster lithography on the GaAs substrate made with a diamond coated probe. Topography (left) and Kelvin mode (right) images. p g p y ( ) ( g ) gLithography is made by surface charging under the layer of GaAs oxide. Topography image shows nothing, when the right image made in SKM mode demonstrates areas charged positively and negatively on the neutral background.
Single-Pass Electric Studies: EFM, KFM, dC/dZ, dC/dV
Working frequencies: mech ≈ 70 kHz;elec = 3-5 kHz; 2nd Eigen mode (2E) ≈ 450kHz;
KFM-AMnon-res dC/dZ-AMnon-resKFM-AMres dC/dZ-AMres – 2E, 3EKFM-PM dC/dZ-PM
3rd Eigen (3E), etcKFM PMnon-res dC/dZ PMnon-res
Multi-Frequency Study of Electrical Properties
Single-Pass and Double-Pass KFM of Fluoroalkanes on Mica
C i f Si l P d D bl P KFM M dComparison of Single-Pass and Double-Pass KFM Modes
F14H20 onF14H20 on mica
Probes for KPFM
FMG01/PtResonance frequency 60 kHz
20 nm
Resonance frequency ~60 kHz
Piezoresponce Force Microscopy (PFM)
Piezoresponse Force Microscopy
TopographyPFM studies of TGS sample.
• Cantilevers (40 N/m) with Pt coating were used for measurements
20 µm
• AC-sample mode with 10V@100kHz applied was used for PFM measurements.
VPFM Amplitude VPFM Phase
20 µm 20 µm20 µm 20 µm
Piezoresponse Force Microscopy
Block scheme of PFM
Hi h T M l l F l i C l f Dii l i B id (DIPAB)
PFM: Non-Orthogonal Domains
Topography Amplitude, VPFM Phase, VPFMHigh-Temperature Molecular Ferroelectric Crystal of Diisopropylammonium Bromide (DIPAB)
PFM: 60V@100kH@
z
Amplitude, LPFM Phase, LPFM4 m 4 m 4 m
DIPAB
DIPAB P f T U h (UC S
426Kb
cDIPAB – courtesy Prof. T. Usher (UC San Bernardino)
4 m 4 m
35
Probes for PFM
Probes for PFM should normally have high spring constants 1 100 N/m and
20 nm
high spring constants 1 – 100 N/m and coating with high conductivity (PtIr, TiN)
Magnetic Force Microscopy (MFM)
MFM Principle
Different magnetic domain structures ofnonhomogenious Yttriumnonhomogenious YttriumIron Garnet (YIG) films. YIG film has substantialvariation of anisotropyvariation of anisotropyfield along the filmthickness
Temperature Dependency
Temperature control: -28 +300°CTemperature control: 28...+300 C
MFM images of the cobalt monocrystal with uniaxialanisotropy. Phase transition occurs when temperature increases. Images obtained from the same area, 14x40 μm. Sample courtesy of Prof. A.G. Pastushenkov, Tver University, Russia.
Domain Structure Transformation in External Magnetic Field
Changes of the domain structure of Au/Co/Au ...Co/Au sandwich t t
Out-of-Plain External Magnet
structure.H = 500 OeH = 0 Oe
H = 1000 Oe H = 1500 Oe
In-Plain External Magnet
MFM Probes
Fig 1 Topography (left) and
MFM_LM – low moment tips
Fig. 1. Topography (left) and Magnetic MFM (right) images of Self-Assembled particle array after Co/Pd thin film depositionafter Co/Pd thin film deposition. Scan size 3x3 um. Sample Courtesy - Prof. Manfred Albrecht, Chemnitz University ofAlbrecht, Chemnitz University of Technology, Institute of Physics
MFM_HC – high correcitivity tips
Nanolithography
Types of Nanolithography
Vector lithographyon OTS layer
Modes: Methods: Regimes:- Force- Voltage- Current
Methods:- Vector- Raster
g- Constant- Gradient- Pulse
3×2 ×4 = 24 Types! Current Pulse
- Pulse Gradient
Force Lithography
Voltage and Current Lithography
Local Anodic Oxidation of Titanium film ilm
Channel width ~20 nm
Precise Closed-Loop Control
Closed-loop OFF Closed-loop ON
Voltage Raster Nanolithography
2 µm1 µm
Nanomanipulation
Carbon nanotubes on silicon substrate. Manipulation of nanotubes in pthe specified direction (before (left), after nanomanipulations (right)).Scan size: 2.6x2.6 µm
Probes for Nanolithography
Diamond Coated Conductive Probes (DCP Series)- DCP01DCP01- DCP10- DCP20
Probes with W2C, TiO, TiN and Pt coatings were also reported to be successfully used in nanolithoapplicationsapplications
Scanning Force Spectroscopy (SFM)
Atomic Force Spectroscopy Principle
Mechanical Properties of the Sample
Force Curves on Different Materials
PDMS60PDMS8 PDMS8
Standard Models for AFM
Rubbery materials: PDMS8, PDMS60 and PDMS 130
PDMS130Models: Hertz, Sneddon, JKR, DMT
Polymer Material
Elastic Modulus Macro
Elastic Modulus AFM
Work of Adhesion Macro
Work of Adhesion AFM
PDMS-8 13.4MPa 13.9MPa 49 J/m2 32 J/m2
PDMS-60 1.61MPa 1.74MPa 58 J/m2 52.2 J/m2
PDMS-130 0.74MPa 0.66MPa 47–58 J/m2 42.1 J/m2
D DForce Curves measured on PS/PBD
PBD
PS
Z Z
Force Curves on Melanoma Life Cell
Images were obtained with use of colloidal probe CPC_SiO2-A
HybriD Mode™
HybriD Mode™ mode: One Curve – Multiple Data
In Hybrid Mode™ the tip-sample distance is modulated according to the quasi-y p p g qharmonic law. Thus tip enters a force interaction with the sample thousands of times persecond. Force-distance curve analysis enables maps of topographical, mechanical andelectrical properties of the sample to be extracted with high spatial resolution.C l H b id d i t h dh i d l ti it i i tCommonly Hybrid mode gives topography, adhesion and elasticity mapping pictures
PS-LDPE BlendT h Adh i E M d lTopography Adhesion E Modulus
Scan Size:Polyethylene blobs on
l t hScan Size: 3×3 µm
polystyrene spheres
E Modulus overlaid over topography
HybriD Mode + Conductivity Mapping
+
Hybrid mode™ was coupled with spreading resistance imaging: a constant y p p g g gDC voltage was applied between the sample and conductive tip. Thus while getting a topography, adhesion and elasticity properties of the sample current going through the circle was recorded.
Complex Study of CNT
Topograpy Current Stiffness
Scan size: 1×1 µm
Image Courtesy: Sergey ZayatsSample Courtesy: Dr. Irma Kuljanishvili, Saint Louis University, Department of Physics
Living Stem Cells
Topography Modulus Map
Post-Processing Capabilities
Revolution Cartridge
Revolution CartridgeInnovative Revolution Head
MFMStiff
SKMSoft
- safe and easy Cartridge replacement - Change methods with the same probes- no system tweaking required (Plug & Play)- high throughput operation
g p~ 40 x less probe replacements
Revolution Cartridge
Find more information at: http://ntmdt com/titaniumFind more information at: http://ntmdt.com/titanium
Thank you for your attention!
All the animations used in presentation can be downloaded at:h // d / i i lhttp://www.ntmdt.com/spm-principles