A volatile memory device can include a bit line structure having a vertical side wall. A lower spacer can be on a lower portion of the vertical side wall, where the lower spacer can be defined by a first thickness from the vertical side wall to an outer side wall of the lower spacer. An upper spacer can be on an upper portion of the vertical side wall above the lower portion, where the upper spacer can be defined by a second thickness that is less than the first thickness, the upper spacer exposing an uppermost portion of the outer side wall of the lower spacer.

A memory cell comprising a substrate, a bit line vertically oriented from the substrate along a first direction, a nanosheet transistor including at least one nanosheet horizontally oriented from the bit line along a second direction perpendicular to the first direction, and a capacitor horizontally oriented from the nanosheet transistor along the second direction.

An apparatus, such as a memory array, can have a memory cell coupled to a first digit line (e.g., a local digit line) at a first level. A second digit line (e.g., hierarchical digit line) at a second level can be coupled to a main sense amplifier. A charge sharing device at a third level between the first and second levels can be coupled to the first digit line and to a connector. A vertical transistor at the third level can be coupled between the first digit line and the connector. A contact can be coupled between the connector and the second digit line.

The present invention discloses a semiconductor memory device, including a substrate, active areas, first wires and at least one first plug. The active areas extend parallel to each other along a first direction, and the first wires cross over the active areas, wherein each of the first wires has a first end and a second end opposite to each other. The first plug is disposed on the first end of the first wire and electrically connected with the first wire, wherein the first plug entirely wraps the first end of the first wire and is in direct contact with a top surface, sidewalls and an end surface of the first end. Therefore, the contact area between the plug and the first wires may be increased, the contact resistance of the plug may be reduced, and the reliability of electrical connection between the plug and the first wires may be improved.

The present invention discloses a semiconductor memory device, including a substrate, active areas, first wires and at least one first plug. The active areas extend parallel to each other along a first direction, and the first wires cross over the active areas, wherein each of the first wires has a first end and a second end opposite to each other. The first plug is disposed on the first end of the first wire and electrically connected with the first wire, wherein the first plug entirely wraps the first end of the first wire and is in direct contact with a top surface, sidewalls and an end surface of the first end. Therefore, the contact area between the plug and the first wires may be increased, the contact resistance of the plug may be reduced, and the reliability of electrical connection between the plug and the first wires may be improved.

A method for fabricating an electronic device comprising a semiconductor memory is described. The method comprises forming material layers over a substrate; forming a hard mask pattern over the material layers, the hard mask pattern including an amorphous carbon layer; forming a capping protective layer including a portion on sidewalls of the hard mask pattern; and etching the material layers using the hard mask pattern as an etch barrier.

An apparatus, such as a memory array, can have a memory cell coupled to a first digit line (e.g., a local digit line) at a first level. A second digit line (e.g., hierarchical digit line) at a second level can be coupled to a main sense amplifier. A charge sharing device at a third level between the first and second levels can be coupled to the first digit line and to a connector. A vertical transistor at the third level can be coupled between the first digit line and the connector. A contact can be coupled between the connector and the second digit line.

A semiconductor memory device including an access transistor configured as a vertical transistor comprises a channel portion and a pair of source/drain regions; a storage capacitor connected to one of the pair of source/drain regions; a bit line connected to the other of the pair of source/drain regions, a first semiconductor layer provided in the source/drain region to which the bit line is connected. Preferably, the first semiconductor layer comprises SiGe.

A volatile memory device can include a bit line structure having a vertical side wall. A lower spacer can be on a lower portion of the vertical side wall, where the lower spacer can be defined by a first thickness from the vertical side wall to an outer side wall of the lower spacer. An upper spacer can be on an upper portion of the vertical side wall above the lower portion, where the upper spacer can be defined by a second thickness that is less than the first thickness, the upper spacer exposing an uppermost portion of the outer side wall of the lower spacer.

Apparatus and methods are disclosed, including memory devices and systems. Example memory devices, systems and methods include an array of memory cells and a transistor located on a periphery of the array of memory cells. A number of data lines are shown coupled to memory cells in the array, wherein the number of data lines extend over a first metal gate of a transistor in the periphery of the array, where the number of data lines are formed from a second metal, and form a direct interface with the first metal gate.