To form a multi-layer structure electrode of high mechanical strength by performing a formation process of a lower layer of a first metal layer, a degas process of a metal target of a second metal layer, a formation process of an upper layer of the first metal layer and a formation process of a second metal layer, in this order, so that adhesive properties of the multi-layer structure electrode is improved.

A p-type ZnTe contact layer 101 is set in a chamber, and then the chamber is evacuated to be a high vacuum condition. Then a Pd target is heated, and a Pd film 102 is formed on a contact layer 101. Then, the Pd target is heated to melt, and a degas process is performed until degree of vacuum is recovered. During this process, an impurity layer 103 is formed on the Pd film 102. After this, when the degree of vacuum is recovered to the extent as much as before formation of the Pd film 102, interrupted formation of the Pd film 102 is resumed, and a Pd film 104 is laminated. After the Pd film 104 is laminated, a Pt film 105, acting as a barrier electrode, is formed. Lastly, an Au film 106, acting as an upper electrode, is laminated, thus a three-layer electrode of Au/Pt/Pd is formed.