| 摘要 |
PURPOSE:To obtain a diode which has software recovering characteristic by forming a region of the same conductive type as a low impurity density region formed between a p type layer and an n type layer and of impurity density higher than the low impurity density region without contact with the p type layer and the n type layer in the low impurity density region, thereby increasing reverse blocking capacity recovering time. CONSTITUTION:An n type low resistance layer 3 is epitaxially grown in a thickness of 2mum on the same surface as that, on which an n type high resistance layer 3 is epitaxially grown in a thickness of 5mum, on one side of a mirror-faced wafer 1. Further, an n type epitaxial layer 4 of the third layer is further grown on the layer 3. The resistivity of the layer 4 is similar to the epitaxial layer of the first layer. Then, in order that an oxidized film 5 is formed on the surface of the wafer and a p type emitter layer 6 is consecutively formed, boron ions are, for example, implanted through the film 5. Subsequently, a p type emitter layer 6 of approx. 1mum in depth is formed by annealing it in nitrogen. In this manner, an aluminum electrode 7 (4mum thick) is formed by vacuum deposition and photoetching technique on the silicon wafer in which the formation of a junction is finished, and the wafer is divided into 4mm.-square chips. |
