Application of optical emission microscopy for reliability studies in 4H-SiC p(+)/n(-)/n(+) diodes

An optical emission microscopy technique with spatial and spectral resoluti on capabilities is applied for stability studies of 4H-SiC material propert ies. From the example of a 4H-SiC p(+)/n(-)/n(+) diode imaged at different stages of electrical overstress the mechanism of degrading performance is d irectly unveiled. We correlate this phenomenon with irreversible structural changes within the active region created by a nonuniform heating related s tress. The stress-generated features are interpreted as multiple stacking f aults spreading throughout the whole base region and nucleated in the vicin ity of built-in defects and process-induced structural deficiencies. (C) 20 01 American Institute of Physics.