High-temperature-processing-induced double-stacking-fault 3C-SiC inclusions in 4H SiC were studied with ballistic electron emission microscopy in ultrahigh vacuum. Distinctive quantum well structures corresponding to individual inclusions were found and the quantum well two-dimensional conduction band minimum was determined to be approximately 0.53 ± 0.06 eV below the conduction band minimum of bulk 4H SiC. Macroscopic diode I-V measurements indicate no significant evidence of metal/semiconductor interface state variation across the inclusions.