A Frequency-EBIC Technique for High Spatial Resolution of the Effective Minority Charge Carrier Lifetime in SiC PN-Junctions

Abstract

We present a new method to potentially map the effective minority charge carrier lifetime by means of a chopped electron beam induced current in a scanning electron microscope using a digital lock-in amplifier. While previous authors have been mainly interested in measuring the diffusion length and some even the minority charge carrier lifetime using line-scans, we show that this method could be extended to measure the lifetime locally in the cross section of a given device. In our case, we use a simple SiC pn-junction. The decrease of current with increasing chopping frequency of the electron beam makes a direct measurement of the effective lifetime possible. Inspired by optical beam induced current (OBIC), this novel approach has great potential to measure the minority charge carrier lifetime locally and is going to help device and process engineers to develop the next generation of SiC power devices.