Big Hole

Symptoms

The NanoFrazor writes a big hole instead of the target pattern even though the depth feedback has already set the force to the minimum (0 V).

trbl_big_hole

Figure 34 Big hole written instead of target field. This happens when the write height is too low and the hot tip touches the PPA surface when no force is applied.

Cause

The hot tip is touching the surface even when no electrostatic force is applied. For further details consult the section on the Forward (writing) Height.

Solution

Increase the write height to separate the tip and sample when the heater is on. If the write height is already larger than 400 nm, decrease the writer temperature/voltage.