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Nano-E
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The Nano-E™ educational AFM system is derived from the industry standard Nano-R™ atomic force microscope (AFM) offered by Pacific Nanotechnology. It is a powerful, multi-purpose AFM for capturing images and measurements of structures with nanometer sized features. Because the Nano-E™ AFM can be used with two versions of image acquisition software, X’pert™ and EZMode™, it is optimized for both novice and expert users. The Nano-E™ includes everything required for AFM imaging: a workstation, a control unit, and the Nano-E™ stage. Also, software for displaying and analyzing images is provided with the Nano-E™AFM. See Figure 1.

Advanced features included with the Nano-E™ include:

• Simple User Interface
• Contact and Close Contact Mode
• Lateral Force and Material Sensing Mode
• Force Distance Curves
• Closed Loop Light Lever AFM Scanner
• High Speed Workstation
• Single 19” LCD Monitor
• Advanced 16/32 bit Controller Architecture
• Enhanced Software Functions
• Scanner Auto-Level
• Store Tilt Function
• Optically Assisted Probe Approach
• Automatic Probe Approach
• Real time XY stage control

Datasheet Contents

1.0 Stage
1.1 Scanner
1.2 Motorized Z Approach
1.3 Sample Holder
1.4 Automated X-Y stage
1.5 Video Optical Microscope
2.0. Workstation/Controller
3.0. AFM Cockpit™ Software
3.1 EZMode™
3.2 X’pert™ Mode
3.3 Image Analysis


1.0 Nano-E™ AFM Stage


The Nano-E™ AFM stage, shown in Figure 2, is a table top unit and can be operated with high resolution results in a normal teaching environment. The stage is optimized for rapidly exchanging samples and probes. An advanced probe exchange mechanism allows exchanging of probes without removing the scanner from the stage. The sample holder is a versatile design so that many types of samples can be accommodated. Once a sample is placed on the sample holding puck, positioning the probe above the sample is rapidly done with the automated X-Y stage and the high resolution video microscope. The Nano-E™ AFM stage includes a sample puck, X-Y positioning stage, Z motorized approach, and a video optical microscope.

1.1 Scanner


The Nano-E™ AFM comes standard with the LL-AFM closed loop scanner. The LL-AFM is ideal for visualizing nanostructures. This scanner is designed for routine topography measurements, and metrology measurements. See Figure 3.

1.2 Motorized Approach

The Nano-E™ AFM includes a unique three motor approach system that is used for moving the AFM probe to the sample for scanning. Each motor has .33” (8.5 mm) of motion, is independently controlled, and includes limit switch sensors. The software for activating the Z approach motors is included with the AFM Cockpit™ software.

1.3 Sample Holder


The Nano-E™ AFM Sample Holder facilitates rapid introduction of a sample to the microscope stage. The holder can accommodate a large variety of sample
sizes. The standard sample holder is for standard magnetic disks. There are several optional sample holders for the Nano-E™ AFM. Additionally, customers
can fabricate their own sample “pucks”. The maximum sample size that the Nano-E™ AFM stage can hold is 3.5” (88.9 mm) X 3.5” (88.9 mm). Custom sample holders can be easily created for special applications. See Figure 4.


1.4 Automated X-Y Translation Stage


The motorized X-Y positioning stage is used for moving the sample “puck” under the AFM probe. The stage is activated from a window on the workstation or it may be
activated from a “trackball”. Under computer control, the stage may be moved to specific locations with user defined step sizes. The stage positioning icon is used for “dragging” the stage to a specific location. Software is used for moving the X-Y sample stage. The window for controlling the stage is illustrated here in Figure 5. The position and rate of travel are software definable.


1.5 Video Optical Microscope


A color video microscope is essential for locating features on a surface for scanning with an AFM. The Nano-E™ AFM has a high magnification, motorized focus video microscope (Figure 6) that is controlled by either software or the system’s trackball. There is a manual control of the X-Y position of the microscope objective for centering the image of the cantilever in the video microscope image.
2.0 Controller & Workstation

The workstation, required for acquiring and analyzing images, uses a state-of-the-art personal computer. Connection of the computer to the control unit is accomplished with a standard Ethernet connector. Specifications for the computer system are improved on a routine basis when improved computer systems are made available. The workstation uses the industry standard WindowsXP™ operating system.

The control unit of the Nano-E™ AFM, shown in Figure 7 is based on a PC 32 bit microcontroller architecture and is connected to the workstation though a standard Ethernet port. Control of x-y scanning is made with 16 bit DAC’s and Z control is provided by extremely low noise analog control electronics.

3.0 AFM Cockpit™ Software

The Nano-E™ AFM has several software modules that are provided with the system. AFM Cockpit™ software operates all the modes for the LL-AFM scanner. The three modules included with the AFM Cockpit™ Software are:

• EZMode™ -- for students and casual users
• X’Pert™ Mode -- for experienced AFM experts
• Image Analysis -- provides AFM image display and analysis

For advanced image analysis and processing, Pacific Nanotechnology offers optional image processing.Software such as NanoRule+™ and SPIP™ from Image Metrology. Optional NanoRule+™ Software modules:

• Grain Analysis Model #P-000-1002-0
• Particle Analysis Model #P-000-1003-0
• DVD Analysis Model #X-000-3000-0

3.1 EZMode™ Software

EZMode™ software uses a simple sequential routine that guides you through the process of acquiring an AFM image. EZMode™ software is ideal for new Nano-E™ AFM operators or students that use the instrument on an occasional basis. The process-oriented software gives a step-by-step procedure for getting an AFM image. At the top of the EZMode™ screen is a sequence of the steps that must be followed (Figure 9). By following these steps it is possible for even the most inexperienced user to get a quality AFM image:




1) Start:
Assure that a cantilever is in the view of the microscope. Place sample in the microscope. Linearize scanner.
2) Select Mode:
Choose contact mode or vibrating mode.
3) Align Laser:
Align the laser on the cantilever.
4) Frequency Sweep:
Perform automatic peak detection for vibrating mode imaging.
5) Stage:
Center tip over the area to be scanned.
6) Tip Approach:
Activate the motors for approaching the sample with the probe.
7) Scan Sample:
Set the scan size and scan parameters.
8) Image Processing:
Visualize and analyze images.
9) Tip Retract:
Move the tip away from the sample surface.


3.2 X’Pert™ Mode Software


Full control of most stage and AFM operations are possible within the X’pert™ software. Below is an example screen from the X’Pert™ software (Figure 10). Figure 11 is a view of the setting card screen for X’Pert™





PhotoDetector Align Window:


This window (Figure 10) facilitates the process of getting the laser aligned on the back of the cantilever and into the photo-detector. A graphic display shows the position of the laser beam on the photodetector. Also, there is an indicator for the total light intensity at the photodetector.

Settings Cards:

All stage and scanner settings can be changed with this series of display “cards”.
There is a separate “card” for each of the stage scanner components that are being controlled. See Figure 11.



Oscilloscope Windows:

There are five oscilloscope windows for displaying the time variation of a signal, a line,
a frequency spectrum, a dual trace scope, and a line scan. Two of these are shown in Figures 12 and 13:





Tip Approach/Retract Window:

The tip button controls all aspects of the tip approach to the sample. The type of approach, rate of approach, and withdrawal are controlled. See Figure 14.


Scan Control Window:


This window (Figure 15), displayed while scanning a sample, shows 2 images and has the scan size, speed, PID setting, and other scan parameters. All scan parameters such as PID, pixels, zoom, and rotation angle are controlled with this window.


3.2 X’Pert™ Mode Software (Continued)

Force/Distance Curve Window: Complete control of force/distance curves is possible with the force distance curve window. See Figure 16.


3.3 Image Analysis Software

All of the commonly available image processing techniques come as standard features with the Nano-R™ AFM system.

Functions that are available are:

• Histogram Analysis
• Plane Correction
• Image Leveling
• Filter
• 3-D Imaging
• Fast Fourier Transform
• Line Profile
• Blending of Images

Each of the processing features is activated with an icon at the top of the analysis window.

Plane Correction:

This window (Figure 17) permits the removal of sample tilt from images. Leveling
methods include 3 point plane, polynomial plane fit, and 1D line leveling. User specified areas may be selected and excluded from the leveling process.


Line Profile:


Several types of line profiles may be selected. They include horizontal, vertical, oblique, polygonal, circular, and several line average. Up to four markers may be selected for analysis. Horizontal and vertical distances may be measured on the line scans. See Figure 18.


Histogram Analysis:

The Histogram Analysis feature, shown in Figure 19, is useful for optimizing the display of AFM images. A region of the image histogram may be selected and used for the full palette range of a displayed image.


Filtering:

Several filtering functions may be applied to an AFM image. Filter options include the blur function, a predetermined filter function, and a conventional kernel. It is possible to select areas of the image that are excluded in the filter process. See Figure 20.


Fast Fourier Transform:


Choose any type of microscope image and then choose a Fast Fourier Transform (FFT) function to be applied to the image. See Figure 21.


3D Imaging:

The 3D imaging features may be viewed from several angles and perspectives. Viewing angles are changed by simply dragging the mouse over the image. See Figure 22.




Specifications

 
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