Measurement of the Diffusion Length in Silicon Wafers with Improved Spatial Resolution

A novel approach for measurement of the minority carrier diffusion length based on 2D non-stationary surface photovoltage theory is developed. It is shown that the spatial resolution is limited by the most value of light beam diameter and diffusion length. It does not depend on the size of a capacitively coupled electrode. A wafer-scale and rapid mapping with high definition (less than 2 min for 7800 point map) is demonstrated.