Contactless Resistivity Measurement Method.
DEPARTMENT OF THE ARMY WASHINGTON DC
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This invention relates to methods and apparatus for contactless, non-destructiveresistivity measurements on semiconducting crystalline material, for example, gallium arsenide. The material to be tested is formed into a disc which is supported within an air gap. The holder for the disc is such as to support the disc only about its outer edges thus, the disc is free to vibrate piezoelectrically. A measuring circuit connected to the electrodes, which establish the air gap, applies an alternating electric field in the air gap which causes the crystal to vibrate. By adjusting the frequency of excitation, resonance may be established in the crystal and by comparing the current drawn through the air gap with graphs previously established for material of the type under test, the resistivity of the disc can be determined. Author
- Electrical and Electronic Equipment
- Test Facilities, Equipment and Methods