Imaging the Surface

Fig. 8 shows a screenshot of EASYSCAN'S scan panel.

Figure 8: The scan panel of the EASYSCAN software

Make sure that the Line Math is ``raw''. Apply the Full and the Start buttons in the scan panel. You should see the measured line scans in the left part of the display. Adjust the Rotation to 0 deg. If the measurement line looks noisy call the assistant (see fig. 9).

Figure 9: Good and noisy measurement lines

If the line scans appear to be of reproducibly good quality, you can adjust the slope of the line with the x-slope parameter. If the line is flat, adjust the Rotation to 90 deg and follow the above steps (see fig. 10.

Figure 10: Adjusting the correct x and y slopes

Then turn back to a rotation of 0 deg. Adjust the view scale and the z-range so that you get a good image of the surface. Test the influence of the different parameters (time/line, points/line, etc.). When adjusting the z-range, make sure that the line scans do not rise into the upper third of the available range. If they do you must apply a larger value for the z. Once you get a good image, take a snapshot by means of the Photo button.
Once you have a good image of the surface, use the Zoom function to decrease the area you are looking at. Aim to choose an area that appears completely flat in the line scans. Take images at approximately 100 nm x 100 nm, 50 nm x 50 nm, 25 nm x 25 nm, 5 nm x 5 nm and 2.5 nm x 2.5 nm scan size. While zooming in, carefully decrease the z-range. Take snapshots of good images. When decreasing the scan range, look at the slope of the individual line scans. Sometimes, they have to be re-adjusted (remember the 90 deg rotation).