Defects are introduced into (11-20) highly N-doped 4H-SiC by one surface scratch followed by annealing at 550°C or 700°C with or without an additional compressive stress. The defects are planar and always consist of double stacking faults dragged by a pair of partial dislocations. In a pair, the partial dislocations have the same line direction, Burgers vector and core composition. All the identified gliding dislocations have a silicon core. An analysis of their expansion during annealing proves that C(g) partial segments can be created but that C(g) partial dislocations are immobile.