A thin-film deposition system has a vacuum chamber and a plasma generator. The plasma generator includes a case, a cathode disposed in the case, an anode assembly disposed at an end of the case, a discharge power supply for applying a discharge voltage between the cathode and the anode assembly, and a gas supply means for supplying a discharge gas into the case. Electrons within a first plasma produced in the case are extracted into the vacuum chamber according to the discharge voltage. An evaporated material in a gaseous state inside the vacuum chamber is irradiated with electrons emitted from the plasma generator to produce a second plasma. The potential at the anode assembly is controlled by anode potential-controlling means such that the electrons within the second plasma are directed at the plasma generator and the ions within the second plasma are directed at the substrate.