420‐nm‐thick polycrystalline silicon films doped with phosphorus after atmospheric‐pressure deposition have been investigated as a function of deposition rate. A correlation between deposition rate and oxygen content into polysilicon film, as determined by electron microprobe analysis, has been established, which accounts for the deposition rate effects on the electrical properties and grain size of the film. Layers deposited at rates lower than about 40 nm/min are characterized by an oxygen content of the order of 1% in weight, which inhibits grain growth during high‐temperature processes and increases sheet resistance by reducing both Hall mobility and carrier concentration.