A compound film of tungsten and germanium useful for semiconductor devices, a semiconductor device using the compound film and a method and an apparatus for manufacturing the compound film. Various embodiments include a compound film of tungsten and germanium, which has a germanium/tungsten composition ratio of 0.2 or more and less than 6 and includes an optical energy gap. The compound film of tungsten and germanium is produced on a substrate by causing a material gas of tungsten and a material gas of germanium to undergo a chemical reaction in at least one of a region in a gas phase and a region on the substrate. Various embodiments include a semiconductor device including a stack structure in which a semiconductor substrate, a compound film of tungsten and germanium having a germanium/tungsten composition ratio of 1 or more and 3.2 or less, and a metal electrode are laminated in this order.