  We investigated the S-doping-driven phase transition from antiferromagnetic
to superconducting in FeTe1-xSx single crystals. The partial substitution of Te
by S suppresses antiferromagnetism in Fe-square lattice. Superconductivity is
induced by oxygen annealing for only FeTe1-xSx in which the long-range magnetic
ordering is suppressed. To realize superconductivity in FeTe1-xSx, both S
concentration enough to suppress antiferromagnetism and oxygen annealing are
required. Anisotropy of superconductivity in oxygen-annealed FeTe0.886S0.114
was estimated to be 1.17.
