Surface potential mapping of p ⁺/n-well junction by secondary electron potential contrast with in situ nano-probe biasing

This article investigates the surface potential distribution of a biased p ⁺/n-well diode using secondary electron potential contrast (SEPC) with an in situ nano-probe trigger. The SEPC image is digitized and quantified for the conversion of the image contrast to the voltage scale, allowing for the identification of the depletion region and the electrical junction. The overlap length between the poly silicon gate and the p ⁺ region is also depicted by two-dimensional (2-D) imaging. This study demonstrates that the proposed in situ nano-probe system is highly effective for surface potential mapping.