Non-contact Thin Layer Conductivity Measurement Based on the Conjugate Magnetic Eddy Current Sensor

Abstract

In order to improve the formation of the eddy current intensity on the thin layer, the high frequency transmission mode is adopted. The conductive layer is in the middle of a pair of conjugated eddy current excitation magnetic field. Eddy current increases measuring circuit current so that the voltage drop of the current on the non sense sampling resistance and the conductance of the thin layer can be obtained. The volume resistivity can be calculated by the thickness of the known thin layer. The electrical conductivity is related to temperature, and can be converted to the standard temperature resistivity of materials in conversion. The conductivity of conductive thin film, polycrystalline silicon and single crystal silicon can be measured by non contact measurement using the high frequency sinusoidal excitation of the eddy current sensor with conjugated magnetic media.