| 摘要 |
PURPOSE:To prevent dielectric breakdown of a memory cell capacitor in the course of manufacturing, by forming an insulating film thinner than the insulating film of the memory cell capacitor, between the upper electrode of the memory cell capacitor and a semiconductor substrate. CONSTITUTION:An N-type well is formed on a P-type silicon substrate. At this time, a low concentration N-type diffusion layer 7 is simultaneously formed around a memory cell array; after LOCOS isolation, a high concentration N-type diffusion layer 2 is formed; a silicon surface is thermally oxidized, thereby forming silicon dioxide films 4, 8. The thickness of the silicon dioxide film 8 is 80Angstrom , but the thickness of the silicon dioxide film 4 is 100Angstrom , because impurity concentration of the diffusion layer 2 is so high that accelerated oxidation is caused. After that, by using a first polysilicon layer 3, the following are formed and a memory cell is completed; the upper electrode of a capacitor, a polysilicon gate layer 5, and a metal layer 6. In this manner, the silicon dioxide film 8 thinner than the silicon dioxide film 4 being the insulating film of a memory cell capacitor is formed, thereby preventing dielectric breakdown of the memory cell capacitor caused by storage of charged particle. |
