Four-probe Instrument for Measuring Sheet Resistance of Microareas and Its Application

The sheet resistance of microareas can be obtained from a modified Van der Pauw formula by using an inclined four probe technique. The tip of probe is put at the corner of the microarea by inspection through a microscope. The condition for precise measurement is analyzed. This instrument has been used to measure the sheet resistance distribution for Boron diffusion chip. In the measuring process, a microprocessor was used to speed up the calculation.