| 摘要 |
PURPOSE:To eliminate the probability of defective writing due to the parasitic PNPN element effect by a method wherein the base.collector junction of a memory cell is deepened by means of changing respective concentration in case of forming bases of peripheral transistor and the memory cell. CONSTITUTION:A dioxide silicon film 12, a silicon nitride film 13 are formed on a collector region 11 and then specified region of the film 13 is removed to form separated oxide films 14. Firstly overall surface is coated with a photoresist film 15 which is removed only from the region to be the base of memory cell to implant ion. Secondly overall surface is coated with another photoresist film 9 which is removed from the region to be the bases of memory cell and peripheral transistor to form respective base regions 16, 16'. Thirdly, after removing the film 13, the memory cell is covered with the other photoresist film 20 and then the film 12 on the region 16 is removed. Finally another dioxide silicon film 21 is grown on overall surface and then the films 21, 21' are changed into phosphorus silicic acid glass films 22, 22' diffusing phosphorus to form emitter regions 23, 23'. |
