| 摘要 |
PURPOSE:To ensure the reliability of a memory of this design, to restrain a standby current consumption from increasing, and to make the memory large in capacity and high in integration by a method wherein an n-type MOSFET, whose gate oxide film is thin and gate length is small, is used as a memory cell transistor and a MOSFET, whose gate oxide film ds thick and gate length is large, is used in a peripheral circuit other than the memory cell of a static type memory. CONSTITUTION:Pull-down n-type MOSFETs Q1 and Q2 and transfer gate n-type MOSFETs Q3 and Q4, which are small in gate length L and whose gate oxide films are made thin to be optimum in thickness corresponding to their gate lengths L, are used in a memory cell MC. Thereby, a static type memory can be made large in capacity and high in integration. N-type and p-type MOSFETs, which are large in gate length and whose gate insulating oxides are thick, are used to constitute circuits other than the memory cell, such as a bit wire load circuit 1, a word wire drive circuit 2, a column transfer gate 3, a control gate 4, a decoder circuit 11, a sense amplifier circuit 12, a write circuit 15, and an output circuit 13. By this setup, a long-term reliability of a gate insulating oxide can be ensured. |
