To obtain a highly reliable semiconductor element which can operate at a high speed and various kinds of device utilizing the element.
Oxygen ions are implanted into a single-crystal silicon substrate 101 and, at the same time, Ni element is introduced to the substrate 101. A silicon oxide layer 105 is thermally formed and, at the same time, a single- crystal silicon layer 106 is obtained. Then a thermally oxidized layer 107 is obtained by heating the substrate 101 in an oxidizing atmosphere containing a halogen element. The formation of the single-crystal silicon layer 106 and the compensation of a defect formed at the boundary between the layer 106 and silicon oxide layer 104 are performed by utilizing the Ni element. In addition, the Ni element is guttered in the thermally oxidized layer 107 at the time of forming the layer 107. When the layer 107 is removed, the concentration of the Ni element can be reduced to such a level that the element does not practically become an issue.