| 摘要 |
PURPOSE:To achieve an economical photoprocess by bringing an emitter elec trode in contact only with the high-impurity-concentration area of a base layer and interposing P-N junctions between the emitter electrode and the base layer area. CONSTITUTION:An emitter electrode 10 is not in contact with N<+> source layer areas 6 but only with a high-impurity-concentration P<+> area 7 joined with the N<+> source areas. P-N junctions 11 are high-impurity-concentration junctions between the areas of about 10<20>cm<-3> impurity concentration and pass a tunnel current therethrough in reverse biasing. Therefore, reverse voltage cannot be stopped; however, the electric potential of the areas 6 is about 0.5-1V higher than that of the area 7. Therefore, the difference in electric potential from a P base layer 5 also exists. Thereby a current value to cause latching is in creased to decrease the frequency of latchings; therefore, no photoprocess is required, a process is shortened, and high accuracy is not required to achieve an economical photoprocess. |
