| 摘要 |
PURPOSE: To increase the number of basic chips in the same area by performing only LDD ion-implantation into a DRAM cell of novel structure while omitting heavily doped ion-implantation. CONSTITUTION: After the first gate oxide film 3, a gate electrode, and a word line polysilicon are deposited without delay, an impurity-implantation process is performed with polysilicon, and using a gate electrode and word line mask, a polysilicon is etched to a predetermined size to form the first gate electrode 4 and a word line 4' pattern. Then, such relatively lightly doped impurity ion- implantation is performed to form the first spacer oxide film 5, and then, such relatively heavily doped impurity ion-implantation is performed to form a substrate MOSFET comprising active regions 6 and 6' of LDD structure. By performing only LDD ion-implantation while omitting heavily doped ion- implantation,a leakage current and punch-through reduction between active regions are minimized, thus the number of basic chips in the same area is increased. |
