The formation and stability of Si1-x C x alloys in Si implanted with carbon ions

Si_1-xC_x alloys of carbon (C) concentration between 0.6%–1.0% were grown in Si by ion implantation and high temperature annealing. The formation of Si_1-x C _x alloys under different ion doses and their stability during annealing were studied. If the implanted dose was less than that for amorphizing Si crystals, the implanted C atoms would like to combine with defects produced during implantation and it was difficult to form Si_1-x C _x alloys after being annealed at 850°C. With the increment of implanted C ion doses, the lattice damage increased and it was easier to form Si_1-x C _x alloys. But the lattice strain would become saturate and only part of implanted carbon atoms would occupy the substitutional positions to form Si_1-x C _x alloys as the implanted carbon dose increased to a certain degree. Once Si_1-x C _x alloys were formed, they were stable at 950°C, but part of their strain would release as the annealing temperature increased to 1 000°C. Stability of the alloys became worse with the increment of carbon concentration in the alloys.