| 摘要 |
PROBLEM TO BE SOLVED: To increase the storage node capacity by forming second conductivity type semiconductor layers and contact layers which connect first and second gate electrodes to first and second conductivity type semiconductor layers on element forming regions. SOLUTION: P ions are implanted into only regions for forming driving transistors at an energy of 150keV and in an amount of 1×10<14> cm<2> through a resist mask to form an n-type semiconductor layer 9-2 beneath a buried oxide layer 2 for forming driving transistors T1, T2. A gate oxide film 10 of 15nm thick is deposited on the entire surface, poly-Si film 12 is deposited and its surface is slightly oxidized, then contact holes C1 are formed as deep as reaching the semiconductor layer 9-2, a W film is deposited on the entire surface to bury the contact holes C1 and etched back to remove the W film on the poly-Si film 12. Thus, the storage node capacity of SRAM cells increases and cell operation is stabilized. |
