Often it is desirable to heat and cool samples so that they can be scanned at temperatures other than room temperature. The limitations of the temperatures that may be used are:

• at the low temperature - condensation on the sample
• at the high temperatures - destruction of the AFM scanner

The practical temperature range is between –20 C and 200 C.

As a sample is heated or cooled, there will be considerable thermal drift in the AFM stage in the XY and Z directions. The thermal drift can only be minimized by making the stage as symmetrical as possible and using low drift materials. Usually there is drift as the stage temperature is raised, and the drift stops when the desired temperature is reached and the stage temperature is stabilized.

FIGURE 2-46 Left: Scanner drift in the x and y axis as a sample is heated in an AFM sample stage. Right: Scanner drift after the sample reaches a specified temperature in an AFM sample stage.

Cooling samples in an AFM stage has another potential problem. Condensation occurs on the components that are being cooled. When cooling a sample in an AFM stage, it is recommended that the entire stage be maintained in a dry environment such as in a glove box.

Typically an AFM scan rate is approximately 1 Hz. A scan with 254 lines