|Chip Size||5 x 5 x 0.3mm²||5 x 5 x 0.3mm²|
|Average interstep distance||0.15 – 0.4 µm||0.2 – 0.5 µm|
|Misorientation of surface||~ 0.2°||~ 0.3°|
|Single step height||0.75 nm||1.5 nm|
|Average roughness of area between steps (terraces)||0.09 nm||0.09 nm|
Calibration of AFM scanner movements along the Z axis in 3 steps
- Place the SiC/1.5 calibration sample on the flat horizontal working area under the AFM probe.
Approach the AFM probe to the sample surface and make topography scanning in the height measure mode using scan size of approximately 10 µm (SiC/1.5) or 5 µm (SiC/0.75). Make sure there are no impurities on the image and choose and area of about 1.5 x 1.5 µm² for further measurements.
- After obtaining a good quality AFM image of the sample surface with several steps, use the software filter to flatten the image so every single step becomes horizontal.
- Choose the area on the AFM image for obtaining height spectra by using possibilities of AFM software. Choose the area with maximum number of steps for better statistics. After obtaining height spectra with peaks corresponding to each step, measure the interpeak distances. Distances between neighboring peaks may vary so it is useful to average distances between peaks by measuring distance between far standing peaks and dividing the measured value by the number of included interpeak distances. Change the scanner calibrating constant while average interpeak distance becomes 1.5 nm (SiC/1.5) or 0.75 nm (SiC/0.75).