Evidence of spontaneous formation of steps on silicon (100)

Extra steps have been found with atomic-force microscopy generated on rather flat silicon (100) surfaces annealed at 1200 ^∘{}C in hydrogen, through a comparison with the surface annealed in argon, which exhibits a typical (Sₐ+Sb) step structure. It is suggested that the extra steps are spontaneously generated due to the relaxation of the strain energy associated with the atomic dimers on the reconstructed surface.