PURPOSE: To be able to perform an impurity doping control without crystal distortion by vapor growing metal compound gas containing radioisotope of a crystal constituent element and transferring it to an impurity by the nuclear decay of the radioisotope.
CONSTITUTION: When a semiconductor crystal layer is formed by a vapor growing method (MOCVD method) using metal compound gas, organic metal compound gas containing radioisotope of constituent element of a crystal to be grown is used, a crystal growth is executed, and it is transferred to an impurity by the nuclear decay of the radioisotope. Since the element of the semiconductor crystal and its radioisotope do not have difference in atomic radius and ion property. Accordingly, even if the crystal growth is performed with metal compound containing the isotope, no disorder occurs in a crystal lattice. When it is transferred to the impurity due to the nuclear decay of the isotope, it is not displaced from the lattice point, no crystal distortion occurs different from the case that the impurity is forcibly doped from externally. Thus, deep impurity level is not formed, n-type impurity doping can be easily controlled.