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Physics of Thin Films

PES 449 / PHYS 549

Thin Film Characterization - Electrical and Magnetic Techniques

 Ohring Chapter 10 Section 10.1.2 (resistance)

Electrical Characterization: Resistance

resistivity = fundamental property of a material

resistance = resisitvity combined with geometry


Four point probe:

four point probe sketch

eliminates resistance of wires

still have contact resistance

need to know spacing of inner probes to convert to resistivity

careful not to puncture film with probes

Van der Pauw method:

Van der Pauw method

placement of measurement points is arbitrary

more mathematical analysis

need two measurements with contacts alternated

Magnetic Characterization

Magnetic properties of thin films can often be described by a hysteresis curve:

hysteresis curve

Magneto-optical Kerr effect (MOKE)

ellipsometry + a magnetic field on the sample

magnetic materials cause an additional rotation of the polarization of reflected light.

typically null out the normal ellipsometry effect and measure the change in intensity of reflected light as the magnetic field changes.

sensitive to thin films


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© Thomas M. Christensen