PURPOSE: To inactivate impurities relatively easily by covering the silicon crystalline face with an amorphous film consisting of silicon oxide or silicon, and then heat-treating it in hydrogen gas atmosphere so as to remove the amorphous film from top of the silicon crystalline face.

CONSTITUTION: An amorphous film 4, which contains many dangling bonds 3, is provided at the surface of an Si crystal 2, which contains electrically active impurity atoms 1, and when it is heated in H2 atmosphere, the adsorption of H2 molecules 5 happens at the surface of the amorphous film 4 at first, and that part diffuses into the amorphous film 4. Since many dangling bonds 3 exist within the amorphous film 4, the H2 molecules 5 are used for the coupling with the dangling bonds 3 and dissociate into H atoms 6, and some H atoms 6 diffuse into the Si crystal 2. And H atoms 6, which have diffused into Si crystal 2, couple with impurity atmos for activation, and form complexes and inactivate these.