| 摘要 |
PURPOSE:To obtain a GTO thyristor provided with a structure, which can improve a turn OFF characteristic, by providing a gate electrode and a cathode region layer at the outside of a first gate region layer through a second gate region layer, which has a concentration lower than the maximum impurity concentration of said first gate region layer. CONSTITUTION:A semiconductor substrate 1 is provided with at least three layers 1-3. The layers having the different conducting types are laminated. An anode electrode 10 is formed on one side of the substrate. A second gate region layer 4, which has the same conducting type as the layer 2 and has the impurity concentration lower than the maximum impurity concentration of the layer 2, is laminated on the surface of the first gate regin layer 2 on the other side of the substrate. A plurality of cathode region parts 5 are provided so that the layer 4 is surrounded and the parts 5 are isolated by recess parts 6 that are provided at the bottom part of the second gate region 4. A cathode electrode 9 is provided on each cathode region part 5. A gate electrode 8 is formed at the bottom of each recess part 6. Thus, the breakdown voltage VGK at the P-N junction between the gate and the cathode can be made large, and the turn OFF characteristic can be improved. |
