Monocrystalline samples of the 4H and 6H polytypes were deformed in compression at 1300C. By using 2-beam bright-field and weak-beam dark-field transmission electron microscopic techniques, the stacking fault energies of these polytypes were determined to be 14.7mJ/m2 (4H) and 2.9mJ/m2 (6H). The experimental values of the stacking-fault energies for the 4H and 6H polytypes were compared with estimates which were obtained from a generalized axial next-nearest neighbour Ising spin model. It was found that the theoretical models predicted a lower stacking-fault energy for 6H-material as compared with that of 4H-material. The predicted energies were within 5 and 40% of the experimental values, respectively.

Stacking Fault Energy of 6H-SiC and 4H-SiC Single Crystals. M.H.Hong, A.V.Samant, P.Pirouz: Materials Science Forum, 2000, 338-342, 513-6