| 摘要 |
PURPOSE:To facilitate the decision whether a product is good or bad by a method wherein an N(P) type epitaxial growth layer is provided in such a way as to cover an N(P) type semiconductor layer that is formed on a P(N) type semiconductor substrate, on the upper surface of which an N(P) type semiconductor layer is provided with an electrode attached. CONSTITUTION:An N<+> type layer is formed on a P type semiconductor substrate layer 5. Next, an N type epitaxial growth layer 8 is formed in such a way as to cover it. Then a P type semiconductor layer 3 that isolates one element from the other is formed in such a way as to surround an N<+> type layer 4 with a distance where the layers 3 and 4 would not join. An N<+> type semiconductor layer 6' is formed on the epitaxial layer 8 surrounded with the isolation layer 3. On the layer 6', an opening for leading out an electrode is provided, where a metal electrode 1 is wired to connect with an external terminal A so that a characteristic test can be performed. Positive voltage applied to the electrode A produces the breakdown voltage in the junction where the N<+> type semiconductor layer 4 and the P type semiconductor substrate 5 meet. Thus, the impurity density (specific resistance) of the P type semiconductor substrate can be detected, which makes it easy to perform the characteristic test and eliminate products that are out of specification. |
