PURPOSE: To obtain a non-single crystal hydrocarbon alloy which has good photoelectric characteristics by using, as material gas, the gas which includes a molecule expressed by a specified formula including R1 and R2 which represent a hydrocarbon substituent or hydrogen.

CONSTITUTION: When a film is deposited, the gas which includes a molecule expressed by a general formula R1COR2 wherein R1 and R2 represent a hydrocarbon substituent or hydrogen is used as material gas. For example, acetone expressed by a chemical formula R1=R2=CH3 is used. First of all, the inside of a vacuum chamber 1 is decompressed and then a substrate 4 on a susceptor 3 is heated, and after the temperature of the vacuum chamber 1 reaches the equilibrium state, the film formation is started. Acetone is kept in a bubbler 26 and is sent to the vacuum chamber and silane is supplied from a silane gas bomb 24. Then, high-frequency waves are applied to a high-frequency electrode 8 and thereby high-frequency plasma is generated between the substrate 4 and the substrate susceptor 3 by discharging. Then, part of the mixed gas of acetone and silane is decomposed and deposited on the substrate 4 as a film and thereby a non-single-crystal silicon carbide alloy of good photoelectric characteristics is obtained.