| 摘要 |
PURPOSE:To make a cell ratio of a driver MOST and to realize a high integration of a memory cell by a method wherein the driver MOST is formed as a buried channel type MOST and a transfer MOST is formed as a surface channel type MOST. CONSTITUTION:A driver MOST is constituted as a buried channel and a transfer MOST is constituted as a surface channel. While a buried layer does not exist under a gate electrode 3' of the transfer MOST, an n-type buried layer exists under a gate electrode of the driver MOST. In addition, when a gate electrode 3' of the buried channel type MOST is constituted of a p-type semiconductor and a gate electrode 3 of the surface channel type MOST is constituted of an n-type semiconductor, a threshold voltage of the individual MOST's can be adjusted to a desired value. By this constitution, a gate width of the driver MOST can be made small while a cell ratio of a memory cell is being secured; as a result, a high integration can be realized easily. |
