PURPOSE: To manufacture the device being small in backward leakage currents and uniform in the characteristics by a method wherein a W which is not alloyed with Al or an alloy containing the W as the main constituent is provided on a surface of an electrode fitted to a semiconductor pellet.

CONSTITUTION: After an N+ type layer for preventing a conduction type inversion due to Al having been disperse-formed on the reverse side of an N type Si substrate 22, an SiO2 film 23 is attached on a surface of the substrate 22 and is made a prescribed pattern by applying a photoetching thereto. Al films 24b and 24a are attached on both sides of the face and the back of the substrate 22, the film 24b is left only within an opening of the pattern on the film 23 side and the film 24b attached on the film 23 is removed to make the pellet 20. On one hand, a W-coat 43 not alloyed with Al is attached on an end surface of a Mo-electrode 12a which is fixed to the pellet 20, the pellet 20 is housed in a glass sleeve 13, the W-film 43 of the electrode 12a is attached on the Al-film side and heat treated in the order of 700°C. Thus, the PN-junction by the Al alloy is achieved within the substrate 22, and the pellet 20 and the coat 43 are strongly coupled.