NOVELTY - The film (10) has a silicon nitride layer (12) formed on a surface of base film (Z). Mean density of a high density region (14) of the silicon nitride layer including 20 percentage thickness of the silicon nitride layer is higher than another mean density of a low density region (16) opposite from the base film, along direction of the thickness of the silicon nitride layer. Third mean density of a middle region with 20 percentage thickness of the silicon nitride layer lies between the other mean densities.    USE - Gas barrier film for use in a display i.e. LCD, and a solar cell. Can also be used for an optical device, organic electroluminescent (EL) display, semiconductor manufacturing device and packaging material to package food, clothing and an electronic component.    ADVANTAGE - The film can be adhered with the base film to provide mechanical strength for the film with high productivity. The film is designed such that radicals are readily produced and density of plasma is decreased. The film utilizes a film deposition unit to achieve productivity in a simplified and improved manner with reduced size of a film deposition device, thus reducing manufacturing cost of the device.    DETAILED DESCRIPTION - The base film includes plastic film/resin film made of organic materials such as polyethylene terephthalate, polyethylene naphthalate (PEN), polyethylene, polypropylene, polystyrene, polyamide, PVC, polycarbonate, polyacrylonitrile, polyimide, polyacrylate and polymethacrylate. The base film can act as a protective layer, an adhesive layer, a light-reflecting layer, a light-shielding layer, a planarizing layer, a buffer layer and a stress-relief layer. INDEPENDENT CLAIMS are also included for the following:    (1) a method for depositing a film    (2) a film deposition device comprising a transport unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic sectional view of a gas barrier film.    Base film (Z)    Gas barrier film (10)    Silicon nitride layer (12)    High density region (14)    Low density region (16)