Jumps in Measured Depth

Symptoms

  • Sudden jumps in the measured depth from one read line to the next one.
  • Featureless or faintly sinusoidal topography in patterned areas.
trbl_lost_contact

Figure 29 Sudden change in measured depth and featureless bottom of patterned areas are typical symptoms of loss of contact during reading.

trbl_lost_contact_3D

Figure 30 Loss of contact only for the deeper patterned areas.

Cause

Loss of contact between tip and surface during reading. Note that when writing 3D structures the loss of contact might only occur for the deeper levels. For further details consult the section on setting the Backward (reading) height.

Solution

Decrease the Backward Height and/or increase the Read Force to keep the tip in contact during reading.