Instruction manual

Cantilever Preparation
Silicon Nitride Cantilever Substrates
66 MultiMode SPM Instruction Manual Rev. B
4.2.1 Tip Shape of Silicon Nitride Probes
Silicon nitride probes provide low cost and durable probes suitable for Contact Mode imaging.
There are some subtleties in general shape that should be understood to gain the best advantage
from the silicon nitride tips when imaging samples with steps of 0.1 to several microns in height.
Bear in mind that the probe tip is approximated by a pyramid formed by intersecting <111> planes
in silicon. The approximate shape of the tip is shown in the upper right in Figure 4.2d. In the same
figure are dimensions and approximate values for spring constants and resonant frequencies.
Figure 4.2d Silicon Nitride Cantilevers—Specifications and Tip Shape
Because the silicon nitride probe tips have lower aspect ratios than single-crystal etched silicon
probes, the steepest measurable step wall angle is appreciably lower. The highest measurable angle
using silicon nitride probes is approximately 65° (Figure 4.2e) using the inner face of the tip
(towards the cantilever holder). The steepest measurable angle from side to side (parallel to the
edge of the probe's substrate) is approximately 55°. Both of these figures assume that the
measurement does not have interference from other edges.
D
C
A
B
35°
4 µm
100 µm Wide 115 122 21 60 0.58** 40
200 µm Wide 193 205 36 113 0.12** 12.3-22.1 †
100 µm Narrow 115 122 15 69 0.38** -
200 µm Narrow 193 205 20 150 0.06** -
Spring constant Measured Fr
A B C D (N/m) (kHz)
45°
Lever Type