Veeco Dimension 3100, Manual

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Cantilever Preparation
Silicon Cantilever Substrates
90 Dimension 3100 Manual Rev. D
6.1.3 Tip Shape of Etched Silicon Probes
Etched silicon probes provide the most consistent tip sharpness of the probes presently available.
There are subtleties in general shape that produce different effects from the etched silicon tips when
imaging samples with steep walls over steps of 100 nm to several microns in height (see
Figure
6.1b ).
Figure 6.1b Theoretical Tip Shape of Silicon Probes
The present process creates a tip which is symmetric from side-to-side with a 17+ 2 ° half cone
angle (see A of
Figure 6.1b ) and asymmetric from front-to-back, along the length of the lever (see
C of Figure 6.1b ).
In addition, the substrate mounting angle also affects the interaction of the tip shape with the
surface. Along the front edge of the tip, the half angle is nominally 25°, while at the back edge of
the tip, the half angle is approximately 10°. Neither of these angles account for the tilt of the
substrate. With the mounting angle of the substrate factored in, the front edge of the tip is 35° and
the back edge of the tip is zero degrees. From the tip side, the cross-section of the tip near the lever
is approximated by an inverted ‘kite’ shape. All of these subtleties arise from the etching process
used to make the tip, which employs caustic solutions to perform wet anisotropic etching of the
silicon.
17.0° 17.0°
Tip
Cantilever
25.0°
10.0°
A
B C