Abstract: A circuit array substrate is provided with thin-film transistors 4 and 5 and PIN diode 6 formed on insulation substrate 3. Active layer 11 and photo-electric sensor portion 21 are made of poly-silicon films. Impurities are doped into active layer 11 and photo-electric sensor portion 21 in the same process chamber, if necessary, to make their impurity concentrations different from each other. Thin-film transistors 4 and 5 with prescribed characteristics and PIN diode 6 with improved photosensitivity can be simultaneously, easily manufactured on insulation substrate 3 with a lesser number of processes.

Abstract: A thin-film forming apparatus of the present invention is capable of reducing variation of film formation rate and forming thin films of a stable thickness. The thin-film forming apparatus can prevent decrease of the film formation rate due to raise of temperatures of an RF electrode and an inner wall of a reaction chamber, by supplying a pressure control gas of a predetermined pressure into the reaction chamber also in non-film formation time to keep a gas pressure in the reaction chamber constant. Thereby, thickness of a film grown on a substrate can be controlled to a constant thickness. Further, by heating the pressure control gas to raise its temperature to a value approximately equal to a temperature of a material gas, variation of the pressure of the gas in the reaction chamber is controlled and the temperatures of the inner wall of the reaction chamber and the RF electrode are kept constant.