A memory device includes a page made up of plural memory cells arranged in a column on a substrate, and a page write operation is performed to hold positive hole groups generated by an impact ionization phenomenon, in a channel semiconductor layer by controlling voltages applied to a first gate conductor layer, a second gate conductor layer, a first impurity region, and a second impurity region of each memory cell contained in the page and a page erase operation is performed to remove the positive hole groups out of the channel semiconductor layer by controlling voltages applied to the first gate conductor layer, the second gate conductor layer, the first impurity region, and the second impurity region. The first impurity layer of the memory cell is connected with a source line, the second impurity layer is connected with a bit line, one of the first gate conductor layer and the second gate conductor layer is connected with a word line, and another is connected with a drive control line; during the write operation after the page erase operation, the positive hole group is formed in the channel semiconductor layer by an impact ionization phenomenon by controlling voltages applied to the word line, the drive control line, the source line, and the bit line; and an applied voltage/applied voltages of one or both of the word line and the drive control line is/are lowered with drops in a first threshold voltage of the first gate conductor layer and a second threshold voltage of the second gate conductor layer.

Material layers including first and second poly-Si layer are formed on a P-layer substrate. Holes which are parallel to each other and each of which is continuous in a first direction are formed in the material layers. The first and second poly-Si layers are each divided by the holes in a second direction orthogonal to the first direction in plan view. Gate insulating layers and P-layer Si pillars are formed in the holes. The P-layer Si pillars are isolated from one another by the gate insulating layers. A dynamic flash memory is formed in which a first gate conductor layer is connected to a plate line, a second gate conductor layer is connected to a word line, the P-layer Si pillars serve as channels, and one of the N.sup.+ layers below and above the P-layer Si pillars is connected to a source line.

Some embodiments include an integrated assembly having digit lines which extend along a first direction, and which are spaced from one another by intervening regions. Each of the intervening regions has a first width along a cross-section. Pillars extend upwardly from the digit lines; and the pillars include transistor channel regions extending vertically between upper and lower source/drain regions. Storage elements are coupled with the upper source/drain regions. Wordlines extend along a second direction which crosses the first direction. The wordlines include gate regions adjacent the channel regions. Shield lines are within the intervening regions and extend along the first direction. The shield lines may be coupled with at least one reference voltage node. Some embodiments include methods of forming integrated assemblies.

A P layer 2 having a band shape is on an insulating substrate 1. An N.sup.+ layer 3a connected to a first source line SL1 and an N.sup.+ layer 3b connected to a first bit line are on respective sides of the P layer 2 in a first direction parallel to the insulating substrate. A first gate insulating layer 4a surrounds a portion of the P layer 2 connected to the N.sup.+ layer 3a, and a second gate insulating layer 4b surrounds the P layer 2 connected to the N.sup.+ layer 3b. A first gate conductor layer 5a connected to a first plate line and a second gate conductor layer 5b connected to a second plate line are isolated from each other and cover two respective side surfaces of the first gate insulating layer 4a in a second direction perpendicular to the first direction. A third gate conductor layer 5c connected to a first word line surrounds the second gate insulating layer 4b. These components constitute a dynamic flash memory.

A semiconductor memory cell includes a floating body region configured to be charged to a level indicative of a state of the memory cell; a first region in electrical contact with said floating body region; a second region in electrical contact with said floating body region and spaced apart from said first region; and a gate positioned between said first and second regions. The cell may be a multi-level cell. Arrays of memory cells are disclosed for making a memory device. Methods of operating memory cells are also provided.

An n.sup.+ layer 3a connected to a source line SL at both ends, an n.sup.+ layer 3b connected to a bit line BL, a first gate insulating layer 4a formed on a semiconductor substrate 1 existing on an insulating film 2, a gate conductor layer 16a connected to a plate line PL, a gate insulating layer 4b formed on the semiconductor substrate, and a second gate conductor layer 5b connected to a word line WL and having a work function different from a work function of the gate conductor layer 16a are disposed on the semiconductor substrate, and data hold operation of holding, near a gate insulating film, holes generated by an impact ionization phenomenon or gate-induced drain leakage current inside a channel region 12 of the semiconductor substrate 1 and data erase operation of removing the holes from inside the substrate 1 and the channel region 12 are performed by controlling voltage applied to the source line SL, the plate line PL, the word line WL, and the bit line BL.

A memory device includes pages containing memory cells arranged in an array on a substrate. In each memory cell, a voltage applied to a first gate conductor layer, second gate conductor layer, third gate conductor layer, first impurity layer, and second impurity layer is controlled to form a hole group by impact ionization inside a channel semiconductor layer, and a page write operation of holding the hole group and a page erase operation of removing the hole group are performed. The first impurity layer is connected to a source line, the second impurity layer to a bit line, the first gate conductor layer to a first plate line, the second gate conductor layer to a second plate line, and the third gate conductor layer to a word line. A page erase operation is performed without inputting a positive or negative bias pulse to the bit line and the source line.

A 3D semiconductor device including: a first level including a single crystal silicon layer and a plurality of first transistors, the plurality of first transistors each including a single crystal channel; a first metal layer overlaying the plurality of first transistors; a second metal layer overlaying the first metal layer; a third metal layer overlaying the second metal layer; a second level is disposed above the third metal layer, where the second level includes a plurality of second transistors; a fourth metal layer disposed above the second level; and a connective path between the fourth metal layer and either the third metal layer or the second metal layer, where the connective path includes a via disposed through the second level, where the via has a diameter of less than 800 nm and greater than 5 nm, and where at least one of the plurality of second transistors includes a metal gate.

A content addressable memory cell includes a first floating body transistor and a second floating body transistor. The first floating body transistor and the second floating body transistor are electrically connected in series through a common node. The first floating body transistor and the second floating body transistor store complementary data.

Methods of maintaining a state of a memory cell without interrupting access to the memory cell are provided, including applying a back bias to the cell to offset charge leakage out of a floating body of the cell, wherein a charge level of the floating body indicates a state of the memory cell; and accessing the cell.