PN-100 Battery Operated PN Type Tester
Theory of Operation
 A semiconductor surface covered by native oxide is typically in depletion conditions regardless of its type. As a consequence the polarity of the surface barrier is characteristic of the conductivity type of the sample under test. Surface barrier polarity can be detected in a non-contact way by measuring the surface photovoltage. During such a measurement a chopped laser light is applied: by the high intensity illumination excess carriers are generated and their presence decreases the surface barrier, i.e. flatband condition is approached. The barrier change due to the illumination is capacitively detected by a probe. Conductivity type is determined by the polarity of the surface barrier change due to illumination.
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| FEATURES: |
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Measurement time:0.5s |
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Red LED = P-type |
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Green LED = N-type
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Resistivity range: from 20 mΩcm to 3000 Ωcm |
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Measurement spot diameter depends on the distance:~10-20mm
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Excitation depth:~5µm
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Measuring distance depends on the resistivity and surface: e.g. for 10cm material with etched surface:~20mm |
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Number of measurements without exchanging the battery:~10000
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Works on Ge, GaAs, and other semiconductor materials
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Type determination of wafers, blocks, pot-scrap, feedstock, etc.
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Works on multi-crystalline and single crystal samples
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Non-contact and completely portable |
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