Luminescence method for the in-line detection of atomic scale defects during fabrication of 4H—SiC diodes

A method of detecting atomic scale defects in SiC semiconductor wafers, comprising the steps of

• scanning the surface of the semiconductor wafers with a field emission scanning electron microscope (SEM) to form an SEM image thereof;
• scanning the SEM image with a light detector and monochromator to obtain a cathodoluminescence (CL) spatial intensity map of the SEM image;
• determining the CL spectra, i.e. the CL intensity against photon energy for each integral CL intensity in the intensity map;
• and
• comparing each CL intensity on the intensity map to a threshold, whereby those CL intensities above the threshold are deemed to indicate a spatial distribution of carbon vacancies in the SiC wafers and unacceptable leakage current.