[en] The authors show that sputtered films of Bi₂Sr₂CaCu₂O_x (BSCCO) deposited onto single crystal MgO substrates held at substrate temperatures T_s, near 700 degrees C and slowly cooled in oxygen, form High Temperature Superconducting (HTS) films with T_czero between 50 and 70 K. The conditions necessary to achieve superconductivity include having close to stoichiometric composition at the T_s required to form the superconductor. Both T_czero and c-axis orientation increase with T_s while the relative bismuth content decreases. Bismuth film content is affected by the type and amount of oxidant, total system pressure, target-to-substrate spacing, and substrate bias. This paper suggests oxygen resputtering of the film may play a role similar to that reported for YBa₂Cu₃O_7-x (YBCO). Oxygen partial pressure during and cooldown rate from T_s to = 350 degrees C also affects the superconducting properties