METHOD OF FORMING RARE EARTH HYDRIDE FILM

PROBLEM TO BE SOLVED : To provide a method for forming a rare earth hydride film where unrequired oxide films are hard to be formed, e.g., on the surface of a rare earth hydride film. SOLUTION : A first substrate 2 with an original rare earth metal film 4 deposited thereon is arranged on the left side in a heating furnace 1, and a second substrate 3 with a rare earth metal film 5 deposited thereon for an impurity getter is arranged on the right side in the heating furnace 1. Then, heating is performed with heaters 6 to 9 while feeding gaseous Ar including hydrogen into the heating furnace 1. Then, at first, the rare earth metal film 5 on the second substrate 3 is hydrogenated, so that a rare earth hydride film 5A is formed, and further, an oxide film is formed, e.g., on the surface of the rare earth hydride film 5A. Thus, in the gaseous Ar including hydrogen passed through the arranging region of the second substrate 3, the concentration of impurity gas is reduced. Next, the rare earth metal film 4 on the first substrate 2 is hydrogenated to form a rare earth hydride film 4A. In this case, unrequired oxide films can be made hard to be formed, e.g., on the surface of the rare earth hydride film 4A.