NON CONTACT METHOD AND APPARATUS FOR MEASUREMENT OF SHEET RESISTANCE AND LEAKAGE CURRENT OF P-N JUNCTIONS

摘要

A contactless sheet resistance measurement apparatus and method for measuring the sheet resistance of a surface p-n junction an its leakage current is disclosed. The apparatus comprises an alternating light source optically coupled with a transparent and conducting electrode brought close to the junction, a second electrode placed outside of the illumination area, and a third grounded electrode surrounding the first and second electrodes. For measurements of junction capacitance, a calibration wafer with known sheet resistance is used to provide reference photovoltage signals. Using the measurement of the junction photovoltage (JPV) sign from the illuminated area and outside this area for calibration and test wafers at different light modulation, frequencies, p-n junctio sheet resistance and conductance (leakage current density) are determined.