Electroluminescent diodes were prepared by the simultaneous diffusion of boron and aluminum at 2150° to 2250°C into nitrogen‐doped,n‐type 6HSiC crystals. These diodes exhibit a typical brightness of 50 ft·L (170 nit) at a current density of 5 A/cm2for temperatures of 25° to above 200°C. The results of various measurements on these diodes are presented and the anomalous nature of the diffusion is discussed.