| 摘要 |
PURPOSE:To reduce the forward voltage drop between an n<-> layer and n<+> layer, and between an p<+> layer and p<-> layer and to improve inverse recovery characteristic by providing the p<+> and n<-> type regions of opposite conductivity type to the n<-> type and p<+> type first and second semiconductor layers with low impurity concentration. CONSTITUTION:On a first n<+> conductivity type semiconductor substrate 1, an n<-> type first semiconductor layer 2 with lower concentration as compared with the substrate 1 is formed, and on the first layer, a p<-> type second semiconductor layer 3 with lower concentration as the layer 2 and substrate 1 is formed thereon. Then in the layer 3, a first region 4 which supplies majority carrier and a second region 5 which absorbes minority carrier injected to the layer 3 are formed. Moreover, a semiconductor electrode 6 which gives mechanical strength to the layers 2, 3 is formed on the layer 3 for over the regions 4, 5. Then, the substrate 1 is removed. Thereafter, a third region 7 which supplies majority carrier to the layer 2 and a fourth region 8 which absorbes minority carrier injected to the layer 2 are formed on the surface of the layer 2. Thereby, a forward voltage drop between semiconductor layers can be reduced and inverse recovery characteristic can be improved. |
