AFM , microscopy

1. NOBUGS
conference
11-05-2002
Camera
“Scanning Probe Microscope” software for
instrument control and data analysis.
E.H. v. Tol – Homan, G. v. Velzen, R. v. Gastel, M. Seynen*
University Leiden, The Netherlands
*Institute for Atomic and Molecular Physics (AMOLF-FOM), Amsterdam
http://www.physics.leidenuniv.nl/sections/cm/ip/ 11-05-2002

2. Overview
Overview
 Introduction to Scanning Probe Microscopes (SPM)
 SPM – software specifications (video rate)
 Instrument control
 Data analysis
 SPM – software architecture
 Conclusion

3. Scanning Probe Microscopes
(SPM)
Scanning Probe Microscopes:
•Scanning Tunneling Microscope (STM)
•Atomic Force Microscopes (AFM)
•…

4. Scanning Probe Microscopes
(SPM)
Scanning Probe Microscopes:
•Scanning Tunneling Microscope (STM)
•Atomic Force Microscopes (AFM)
•…
The Scanning Tunneling Microscope works like a record player…

5. Scanning Probe Microscopes
(SPM)
X,Y
Scan
circuit
Piezo
Feedback
Electronics PC
specimen
U sample
Z
It
tip

6. Scanning Probe Microscopes
(SPM)
Line scan image of graphite
surface. Each bump
corresponds to a single carbon
atom. The size of the image is
only 3 nm  3 nm.
15
years
Ago:
Now:
Perspective color view of
Graphite surface
“Photo
Camera”

7. Scanning Probe Microscopes
(SPM)
New “Video camera”
High speed scanning probe microscope:
•25 pictures (256 x 256) per second
•Maximum scan speed: 3,3*106 pixels/sec

8. Scanning Probe Microscopes
(SPM)
Au (110)
Usample =-0.7V
~ 22000 pixels/sec
300 nm x 300 nm

9. Scanning Probe Microscopes
(SPM)
Au (110)
Usample =-0.7V
~ 134000 pixels/sec
300 nm x 300 nm

10. SPM – software specifications
Computer specification for a high speed SPM:
 Dual processor:
first processor: data display / analysis / scaling
second processor: instrument control
 Dual monitor:
first monitor data display
second monitor instrument control - window

11. SPM – software specifications
General specifications for a high speed SPM:
1. Two “user modes of operation”:
online and offline mode.
Online Mode
-measurement
-analysis
Offline Mode
-Post measurement analysis
GUI

12. SPM – software specifications
Online Mode Offline Mode
GUI
General specifications:
2. The program uses a DLL to configure and drive the
hardware of the SPM. (Different DLL’s for each SPM)
STM- DLL …
AFM- DLL

13. SPM – software specifications
Boundary requirements:
 Very stable and reliable
 Fast data handling and graphics
 Extendable, Users can add own filters
 Windows look and feel
 RECOVERY PROCEDURE !

14. SPM – software specifications
Why winNT (decided three years ago) ?
 Multi tasking operating system
 Drivers for microEnable / hotlink only available under
winNT.
 Commonly know environment
 Offline mode can run under windows 98,2002, XP
RT/Time-sharing
 Real-time part: dedicated hardware
 Time sharing – part: winNT (GUI).

15. SPM – software specifications
A collection of C++ classes and an application framework
for creating Microsoft windows-based applications.
Document / View structure

16. SPM – software specifications
Document / View structure:
SPM – DATA

17. Instrument control
GUI
Online Mode
-measurement
-analysis
Offline Mode
-Post measurement analysis

18. Instrument control
MAIN SPM
DLL
Data display
Instrument control

20. Instrument control
Measurement mode:
1. Approach (bringing the tip to the surface)
2. Setting scanning parameters
3. Scan (with video rate)
4. Save
During measurement analysis and display through main
program.

21. Data analysis
GUI
Online Mode
-measurement
-analysis
Offline Mode
-Post measurement analysis

23. Data analysis

24. Data analysis
Height line:

25. Data analysis
3D:

26. Data analysis
Filter functions:
Clipping: image size adjust
Filters:
Differentiate,
Background subtraction
…
FILTER
DLL
MAIN
USER DEFINED DLL

27. Data analysis
Original
data:

28. Data analysis
Background
subtraction:

29. Data analysis
Differentiate
(line by line)
data:

30. SPM – software architecture
Architecture
Online Module Offline Module
GUI
STM- DLL AFM- DLL

31. SPM – software architecture
The interface (for Instrument Control) DLL:
 MFC DLL, dynamically linked to the
MFC-libraries.
 Init Instance / Exit instance are called
when the DLL is loaded / freed from memory.

32. SPM – software internally
MAIN DLL
SendSPMCommand
This function is defined
in the DLL, and called
by the MAIN.
SendNotify
This function is defined
in the MAIN, and called
by the DLL.

33. SPM – software internally
MAIN DLL
SendSPMCommand
This function is defined
in the DLL, and called
by the MAIN.
Set / GetDeviceConfig
GetDeviceStatus / GetLastError
CommandWindowCreate / Close
…

34. SPM – software internally
MAIN DLL
SendNotify
This function is defined
in the MAIN, and called
by the DLL.
StartScanMeasurement
UpdateFrameData
StopScanMeasurement
…

35. SPM – software internally
Threads overview
MEASUREMENT
GUI
DISPLAY
Thread
Safe

36. SPM – software internally
DLL
Hardware
Message
Loop
Disk

37. SPM – software internally
Message
Loop
MAIN
Process Filters

38. Conclusion
A graphical user interface for
a high speed SPM (with video rate) has
been developed using MFC and winNT.
NO BUGS

39. Interface physics group
The Team:
Prof. Dr. J.W.M. Frenken (Group leader)
Dr. ir. T.H. Oosterkamp (Group leader)
Dr. M.J. Rost (Post-Doc)
Ir. K. Schoots (Ph.D. Student)
R. v. Gastel (Ph.D. Student)
Ing. B. Crama (Electronics) *B. Okhuysen (Group leader)
Ing. P. Schakel (Electronics) *Ing. M. Seynen (Software)
Ing. E.H. v. Tol-Homan (Software) *Ing. H. Dekker (Electronics)
Ing. G. v. Velzen (Software) *Ing. A. Vijftigschild (Electronics)
*AMOLF/FOM
Email: vantol@fwneld.leidenuniv.nl
Web page: http://www.physics.leidenuniv.nl/sections/cm/ip/