| 摘要 |
PURPOSE:To improve the speed of operation by a depletion layer extending from control electrodes to covere most of a current path, another depletion layer extending from two main electrodes to cover a current path between the same electrodes, and by minimizing the storage of minority carriers. CONSTITUTION:In a junction-type bipolar transistor, the impurity concentration Nb in a p<->-type base layer and the measurement of the layer (w for the distance between p<+> control electrodes and l for the distance between an n<+> type emitter layer and an n-type collector layer) are set forth as follows. When a diffusion potential between layer 2 and control electrode layer 5 and that between layer 2 and collector layer 3 are represented by Vb and Vb2, respectively, and in order to allow depletion layers to cross layer 2 only by each diffusion potential, calculation may be carried out by the given formulas wherein epsilon stands for dielectric constant at 0 deg.C and g for net electric charge. The results show that electrons from emitter 1, although present in p<->-layer 2, do not behave as minority carriers, but are given drift mobility in the presence of electric field, resulting in the loss of storage therein. Then the capacity between electrodes is reduced because of the depletion of layer 2, causing to improve the speed of operation. |
