Luminescence imaging of extended defects in SiC via hyperspectral imaging

Over the past decade, improvements in silicon carbide growth and materials have led to the development of commercialized unipolar devices such as Schottky diodes and MOSFETs. However, much work remains to realize the goal of wide-scale commercialization of both unipolar and bipolar devices, such as pin diodes or IGBTs, for applications requiring high powers, operating at elevated temperatures or in radiation environments or for many fast switching applications. Despite the great strides that have been made in reducing extended and point defect densities during this period, such defects still remain and, with the push to lower off-cut angle substrates, are in many cases seeing increases in prevalence. Thus, spectroscopic and imaging techniques for locating and identifying these defects are in high demand. Luminescence imaging and spectroscopy have both been utilized heavily in such work, yet simultaneously obtaining corresponding spectroscopic and spatial information from such defects is problematic. Here we report on hyperspectral imaging of electroluminescence from SiC pin diodes, whereby a stack of luminescence images are collected over a wide spectral range (400-900 nm), thereby providing the ability to simultaneously image distinct features and identify their corresponding spectral properties. This process is also equally applicable to collecting either photo- or electroluminescence from other materials or devices emitting in either the UV-Vis or NIR spectral range, as well as to reflectance, transmission or other imaging techniques.