Veeco Dimension 3100
Atomic Force Microscope
Urs Manual
Coral name: AFM1
Model: Veeco Dimension 3100
Location: Nanofab, Building 215
Contact: nanofab_v
Revision: 1.0
TappingMode AFM
Feedback Loop Electronics
TappingMode AFM operates by scanning a tip attached to the end of an oscillating cantilever across the sample surface.鸡内金炒与不炒的功效与作用
The cantilever is oscillated at or slightly below its resonance frequency with an amplitud e ranging typically from 20nm to 100nm. The tip lightly “taps” on the sample surface during scanning, contacting the surface at the bottom of its swing.
The feedback loop maintains a constant oscillation amplitude by maintaining a constant RMS of the oscillation signal acquired by the split photodiode detector.
The vertical position of the scanner at each (x,y) data point in order to maintain a constant “tpoint” amplitude is stored by the computer to form the topographic image of the sample surface. By maintaining a constant oscillation amplitude, a constant tip-sample interaction is maintained during imaging.
Operation can take place in ambient and liquid environments. In liquid, the oscillation need not be at the cantilever resonance.
When imaging in air, the typical amplitude of the oscillation allows the tip to contact the surface through the adsorbed fluid layer without getting stuck.
TappingMode AFM
Advantages:
荡气回肠什么意思• Higher lateral resolution on most samples (1nm to 5nm).
• Lower forces and less damage to soft samples imaged in air.
• Lateral forces are virtually eliminated, so there is no scraping.
Disadvantages:
• Slightly slower scan speed than contact mode AFM.
Abbreviated Instructions for the MultiMode AFM
Mode of Operation
In the Other Controls panel, t AFM Mode to Tapping, Contact, or choo the appropriate profile and change the mode switch on the ba to TMAFM or AFM & LFM mode, respectively.
轮滑鞋怎么选Mount Probe
1. Mount a probe into the cantilever holder. Be sure that it is in firm contact with the end of the groove.
• Tapping: U an etched single crystal silicon probe (TESP).
• Contact: U a silicon nitride probe (NP).
2. Put the cantilever holder in the optical head. Secure the holder by tightening the screw in the back of the optical head.
从此Select Scanner
Choo a scanner (A, E, or J). Mount and plug the scanner into the ba. Attach the corresponding springs to the microscope ba. In the software, choo the appropriate scanner parameters with Microscope > Select.
Mount Sample
Mount a sample on a metal disk with a “sticky-tab” (sample width should be limited to the disk’s 15mm diameter). Mount the disk and sample on top of the scanner.
Place Optical Head on Scanner
车上路上完21. Rai all three coar-adjust screws on the scanner so that there is enough clearance between the tip and sample when the optical head is placed on the scanner. If using a JV or EV scanner, you only need to rai the motor screws.
2. Place the optical head on the scanner, still checking that the tip doesn’t touch the sample. Attach the springs to the optical head.
3. Plug in the connector from the optical head to the ba.
4. Bring the tip clo to the sample keeping the head level by lowering all three coar-adjust screws.
Align Lar and Tip-Sample Approach (2 Methods)
空调衣1. Magnifier Method for Aligning Lar and Tip-Sample:
a. Focus on the side-view of the cantilever with the magnifier. If you are having trouble finding the cantilever, try arching for the red light of the lar and focus on that. U the “paper method” describ ed below for positioning the lar spot on the cantilever:
b. Move lar until it is at the front edge of the cantilever substrate. Move lar just off the front edge and move laterally along the edge looking for the reflection of the lar spot from the cantilever onto the paper. Center the lar on the cantilever at its end.
c. Keeping the optical head level, focus on the lar reflection of the cantilever and sample to bring the cantilever clo to the sample. U screws at the ba of the optical head (front and left) to position the cantilever over the area of interest on the sample.
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2. Optical Viewing Microscope Method for Aligning Lar and Tip-Sample
a. Place the microscope on the optical microscope positioning stage.
b. Turn on the monitor and the light source.
c. Focus on the cantilever (zoom out, if using optical microscope equipped with zoom). U the ba screws on the stage of the optical microscope to center the cantilever in the field of view. Lower the focus of the optical microscope to the sample surface. You will still e an out of focus “shadow” of the cantilever in the field of view. Keep the optical head level while lowering the cantilever until it is almost in the same plane of focus -keep the shadow of the cantilever in the field of view at all times. It is helpful to go up and check the focus on the cantilever from time to time to e how clo it is to the sample surface.
d. Once the cantilever is clo to the sample surface, adjust the lar so that it is positioned over the cantilever. U the two screws at the top of the optical head to move the red lar spot onto the cantilever. You may need to change the field of view of the optical microscope initially to find the lar spot.
e. Next u the “paper method” (as described under Magnifier Method) to fine position the lar spot on the cantilever. U the two screws at the ba of the optical head (front and left) to position the ca
ntilever over the area of interest on the sample. As the stepper motor moves during engagement, the cantilever will shift towards the back of the microscope (unless you are using a Vertical Engage Scanner). This means that you should place the cantilever in front of (below on the monitor) the area where you want to engage.
Adjust Photodiode Signal
Note where the lar reflection enters the photodiode cavity. If necessary, adjust the mirror (lever on back of optical head) to center the lar reflection into the photodiode cavity. Leave the mirror at an angle such that the SUM signal (circular meter in bottom LCD) is maximized.
• Tapping: Adjust the Vertical Difference value (bottom LCD) to zero using the screw on the top left side of the optical head.
• Contact: Set the Contact AFM Output Signal value (Vertical Difference, top LCD) to -2.0V using the screw on the top left side of the optical head. Adjust Horizontal Difference value (bottom LCD) to zero using the screw on the back, left side of the optical head.
Cantilever Tune (TappingMode Only)
Select View > Cantilever Tune (or lect the Cantilever Tune icon). For Auto Tune Controls, make sure Start Frequency is at 100 kHz and End Frequency is at 500 kHz. Target Amplitude should be 2-3 volts. Click on Auto Tune. A “” sign should
appear and then disappear once Auto Tune is done. When finished, quit the Cantilever Tune menu.
Set Initial Scan Parameters
In Scan Controls panel, t the initial Scan Size to 1 μm, X and Y Offts to 0, and Scan Angle to 0.
• Tapping: In the Feedback Controls panel, t Integral Gain to 0.4, Proportional Gain to 0.6, and Scan Rate to 2 Hz.
粮食直补
• Contact: In the Feedback Controls panel, t the Setpoint is to 0 volts, the Integral Gain to 2.0, the Proportional Gain to 3.0, and the Scan Rate to 2 Hz.
Engage
Select Motor > Engage (or lect the Engage icon).
Adjust Scan Parameters
Tapping
a. Select View > Scope Mode (or click on the Scope Mode icon). Check to e if the Trace and Retrace lines are tracking each other well (i.e. look similar). If they are tracking, the lines should look the same, but they will not necessarily overlap each other, either horizontally or vertically.
b. If they are tracking well, then your tip is scanning on the sample surface. You may want to try keeping a minimum force between the tip and sample by clicking on Setpoint and Realtime using the right arrow key to increa the Setpoint value gradually, until the tip lifts off the surface and the Trace
and Retrace lines no longer track each other. Then decrea the Setpoint with the left arrow key until the Trace and Retrace follow each other again. To make sure that the tip will continue to track the surface, it is best to decrea the Setpoint one or two arrow clicks more with the left arrow key. Then lect
View > Image Mode (or click on the Image Mode icon) to view the image.
c. If they are not tracking well, adjust the Scan Rate, Gains and/or Setpoint to improve the tracking. If Trace and Retrace look completely different, you may need to decrea the Setpoint one or two clicks with the left arrow key until they start having common features in both scan directions. Then, reduce Scan Rate to the lowest speed with which you feel comfortable. For scan sizes of 1-3μm try scanning at 2Hz; for 5-10μm, try 1Hz; and for large scans, try 1.0-0.5Hz. Next, try increasing the Integral Gain using the right arrow key. As you increa the Integral Gain, increa the Proportional Gain as well (Proportional Gain can usually be 30-100% more than Integral Gain). The tracking should improve as the gains increa, although you will reach a value beyond which the noi will increa as the feedback loop starts to oscillate. If this happens, reduce the gains until the noi goe
s away. If Trace and Retrace still do not track satisfactorily, the last thing to try is to reduce the Setpoint. Once the tip is tracking the surface, lect
