| 摘要 |
PURPOSE:To provide a gate turn-off thyristor of high performance in which turning-ON and turning-OFF characteristics can cooperate mutually by reducing the densith of a cathode region opposed to said cathode region which approaches a gate electrode smaller than the other region and expanding a conductive region at the turning-ON time from this part. CONSTITUTION:Gallium is diffused from both side surfaces of a substrate N1 to form P1 and P2 layers. Then, an oxidized film is formed on the overall surface, and a window is opened at the oxidized film to form a high impurity density layer in the prescribed pattern. After a selectively diffused oxidized film is formed by the prescribed method, boron is diffused through a window which is opened at an oxidized film 12 on the surface of the P2 layer. An oxidized film is again formed on the overall surface, a window is opened at the position interposed between the boron diffused layers at the oxidized film, a low density layer 6 is formed. After a P type single crystal layer 14 is epitaxially grown on the entire surface, phosphorus is selectively diffused in the epitaxial layer in the pattern of the cathode N2 layer to form an N2 layer 5. Then, a lifetime is controlled as required and electrodes are bonded to form a GTO. |
