Abstract: A highly reliable light-emitting device is provided. Damage to an element due to externally applied physical power is suppressed. Alternatively, in a process of pressure-bonding of an FPC, damage to a resin and a wiring which are in contact with a flexible substrate due to heat is suppressed. A neutral plane at which stress-strain is not generated when a flexible light-emitting device including an organic EL element is deformed, is positioned in the vicinity of a transistor and the organic EL element. Alternatively, the hardness of the outermost surface of a light-emitting device is high. Alternatively, a substrate having a coefficient of thermal expansion of 10 ppm/K or lower is used as a substrate that overlaps with a terminal portion connected to an FPC.

Abstract: A technique of reducing fluctuation between elements is provided in which a semiconductor film having a crystal structure is obtained by using a metal element that accelerates crystallization of a semiconductor film and then the metal element remaining in the film is removed effectively. A barrier layer is formed on a semiconductor film having a crystal structure by plasma CVD from monosilane and nitrous oxide as material gas. In a step of forming a gettering site, a semiconductor film having an amorphous structure and containing a high concentration of noble gas element, specifically, 1×1020 to 1×1021/cm3, is formed by plasma CVD. The film is typically an amorphous silicon film. Then gettering is conducted.