To provide an element for detecting semiconductor neutron rays that has stable sensitivity over a long time and has is highly reliable.

An amorphous silicon layer 2 is formed on a single crystal silicon plate 1, an upper aluminum electrode 3 is formed on the amorphous silicon layer 2, and a lower aluminum electrode 4 is formed on the single crystal silicon plate 1, thus constituting a hetero-junction-type diode structure. A boron layer 5 is formed on the upper aluminum electrode 3, and an aluminum-covering layer 6 is formed so that the boron layer 5 is covered. The boron layer 5 is covered by the aluminum-covering layer 6, thus preventing the boron layer 5 from being released. It is also effective that poly-p-xylene deposition layer is formed instead of the aluminum-covering layer 6. Also, a method can be similarly applied to a pn-junction-type or a surface-barrier-type diode structure.