The effects of fluorine on the performance of solar cells with polysilicon contacts at the front surface and at both: front and back surfaces, are reported. It is shown that a fluorine implant applied to the front surface of the device has two different effects: it improves the passivation of the free oxidised surface leading to improvements in open circuit voltage and short circuit current, and it reduces the series resitance. The back polysilicon contact improves the back interface recombination velocity. Specific series resistance Values from 0.16 to 0.5 Ohm cm(2) have been measured. The effects of the polysilicon contact processing conditions on the short-circuit current, open-circuit voltage and spectral response are also discussed.