Energy-Filtered Secondary-Electron Imaging for Nanoscale Dopant Mapping by Applying a Reverse Bias Voltage

We observed the dopant contrast of an InP structure with magnifications as high as 250,000 by simultaneously applying secondary electron energy-filtering and a reverse bias voltage. The detection modes without energy-filtering and without a bias voltage did not generate a clear contrast. This was because the reverse bias increased the contrast and relatively decreased the sensitivity to the contamination layer while the energy-filtering reduced the influence of the contamination layer, even at a high magnification. This method can be widely used for semiconductor devices and enables practical nanoscale dopant mapping with a high data acquisition rate, and is therefore expected to greatly assist in extending the frontiers of the semiconductor industry.