| 摘要 |
PURPOSE:To obtain a semiconductor memory device, which can perform nondestructive reading, by providing a first conducting layer and a second conducting layer, which are isolated from each other, and providing a second impurity region, which has the same conducting type as that of a semiconductor substrate neighboring the side surface of an inner groove that is formed in the surface of a first impurity region between the inner groove and an outer groove. CONSTITUTION:In reading, a reading bit line 22 is made to be 0[V], and a word line is made to be, e.g. -3[V]. When an N-type impurity region 13 between an inner groove and an outer groove 16 is 5[V], an MOSFET becomes an OFF state. The MOSFET is composed of a gate electrode comprising a first polycrystalline layer 18 and source and drain regions comprising a P-type impurity region 20 and a P-type silicon substrate 11. When the region 13 is 0[V], the MOSFET becomes an ON state, and a current can be sensed. Namely, the reading is performed by utilizing. the change in threshold voltage of said MOSFET. At this time, by varying the potential of the N-type impurity region 13 between the inner groove 15 and the outer groove 16 up and down, the threshold voltage of the MOSFET, which is provided in this region, is varied up and down. Thus the data is read out. |
