Characterization Techniques in Nanotechnology …
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outermost probes. If the sample has resistance, there will be a voltage drop when the
current flows along the sample. The voltage change is measured through two inner
probes. Figure 32a shows KLA-Tencor OmniMap RS75 four-point probe often used
to measure the average film resistance. The general mechanism of measurement based
on four-point probe is shown in Fig. 32b. For a sample of semi-infinite volume, a
very thin layer (thickness t « s), and equal interprobe spacing s, the sheet resistivity
ρ is given by Eq. 16:
ρ =
π t
ln2
V
I
(16)
Fig. 32 a KLA-Tencor OmniMap RS75 four-point probe (the inset is the measuring table), b mechanism of measurement showing the arrangement of the four probes on sample, c resistivity, hall
mobility, and carrier concentration against thickness of ultrathin poly-SiGe film (Asafa et al. 2014)
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outermost probes. If the sample has resistance, there will be a voltage drop when the
current flows along the sample. The voltage change is measured through two inner
probes. Figure 32a shows KLA-Tencor OmniMap RS75 four-point probe often used
to measure the average film resistance. The general mechanism of measurement based
on four-point probe is shown in Fig. 32b. For a sample of semi-infinite volume, a
very thin layer (thickness t « s), and equal interprobe spacing s, the sheet resistivity
ρ is given by Eq. 16:
ρ =
π t
ln2
V
I
(16)
Fig. 32 a KLA-Tencor OmniMap RS75 four-point probe (the inset is the measuring table), b mechanism of measurement showing the arrangement of the four probes on sample, c resistivity, hall
mobility, and carrier concentration against thickness of ultrathin poly-SiGe film (Asafa et al. 2014)