B13-O-10Low Energy Secondary Electron Imaging for Various Semiconductors using Fountain Detector

Abstract

Recently, the energy filtered secondary electron (SE) images give fruitful information of the specimen, not only morphology and composition but also surface potential, electrical field etc. Such modern detector has been developed for inlens SEM and outlens detectors were abandoned. We have developed low-pass secondary electron detector (LPSED) for outlens SEM and named “Fountain Detector (FD)”. This detector is composed of bias grid above and electron detector below the specimen. The bias voltage and the geometry of the detector limit the energy and acceptance angle of SE, respectively. The biggest advantage of FD detector is that we can easily trace the trajectories of the secondary electros. Fig. 1 shows the photograph of prototype FD. The subtraction of the images taken different bias voltages gives the energy filtered images. Using this detector, we have characterized various semiconducting materials. In this presentation we demonstrate the observations of surface potential variation of GaN islands on Si substrate and p-n junction of SiC wafer.