Effects of surface roughness and single Shockley stacking fault expansion on the electroluminescence of 4H-SiC

Abstract

The electroluminescence of a 4H silicon carbide (SiC) bipolar junction transistor was studied using the base-collector junction after a side-wall facet was exposed. This sidewall was ground and polished in sequential stages with increasing grit numbers. After each stage, an electrical stress test under forward bias was performed. Electroluminescence spectra with peaks at 390 nm, 445 nm and 500 nm were initially observed. These peaks were seen to evolve under operation and after changes to the surface condition. Expansion of single Shockley stacking faults (1SSFs) in the device was observed during forward biased operation as evidenced by the growth of the 420nm emission peak, while the broad 500 nm peak was seen to diminish with increasing surface smoothness. Defect-enabled radiative recombination in SiC is a useful pathway for SiC defect characterization and it offers a new opportunity for light emission from SiC.