| 摘要 |
PURPOSE:To increase an emitter injection efficiency and thereby to improve the characteristic of a reverse transistor by reducing the density of an emitter, a base and a collector in this order and by connecting the emitter directly with the base. CONSTITUTION:B irons are injected selectively in a poly-Si layer 2 on an N<+> type Si substrate 1 to form P layers 2a and 2b, poly-Si 7 is laid thereon, P ions are injected therein, and thereby an N layer 10 is formed. Then B ions are injected again with an SiO2 mask 9 used, whereby P layers 7b and 7c are formed selectively. When laser annealing 15 is applied, the poly-Si layer alone is melted to crystallize, impurities are activated, thereby single-crystal layers 22 and 27 are formed on the N<+> substrate 1, and, being surrounded by these layers, a P base 16, an N multicollector 17 and a P injector 18 are completed. At this time, an inverted N-P-N transistor is already formed, the density is reduced in the emitter 1, the base 16 and the collector 17 in this order, and the distribution thereof is sharply changed in the vicinity of P-N junction. Accordingly, the expansion of a depletion layer toward the side of the base is restrained and thus the characteristic of the reverse transistor can be improved. |
