The Si-rich 3 x 3 to Si-terminated √3 x √3 phase transition of the 6H-SiC(00•1) surface was investigated by means of atomically-resolved scanning tunnelling microscopy. A 2√3 x 2√3-R30° reconstruction was found which coexisted with a few 3 x 3 domains. While a high-quality 3 x 3 surface preparation was achieved with a very low defect density (<2% of atomic defects), the (2√3 x 2√3)-R30° reconstruction instead exhibited long atomic cracks suggesting important stress relief during the phase transition. A structural model containing 13 Si atoms per unit cell distributed in three layers above the Si terminated bulk SiC substrate was proposed.

Atomic Cracks and (2√3 x 2√3)R30° Reconstruction at 6H-SiC(0001) Surface. F.Amy, P.Soukiassian, C.Brylinski: Applied Physics Letters, 2004, 85[6], 926