Embodiments of a three-dimensional (3D) memory device and fabrication methods thereof are disclosed. In an example, a 3D memory device includes a memory stack having a plurality of stairs. Each stair may include interleaved one or more conductor layers and one or more dielectric layers. Each of the stairs includes one of the conductor layers on a top surface of the stair, the one of the conductor layers having (i) a bottom portion in contact with one of the dielectric layers, and (ii) a top portion exposed by the memory stack and in contact with the bottom portion. A lateral dimension of the top portion may be less than a lateral dimension of the bottom portion. An end of the top portion that may be facing away from the memory stack laterally exceeds the bottom portion by a distance.

A method of forming a memory device is provided. The method comprises: forming a first storage portion on a substrate; forming a conductive layer on the first storage portion, wherein the conductive layer has a first surface coupled to the first storage portion; and forming a second storage portion on a second surface of the conductive layer, wherein the second surface is opposite to the first surface.

A microelectronic device comprises a stack structure, a stadium structure within the stack structure, and conductive contact structures. The stack structure comprises a vertically alternating sequence of conductive structures and insulative structures arranged in tiers. Each of the tiers comprises one of the conductive structures and one of the insulative structures. The stadium structure comprises a forward staircase structure having steps comprising edges of the tiers, and a reverse staircase structure opposing the forward staircase structure and having additional steps comprising additional edges of the tiers. The conductive contact structures vertically extend to upper vertical boundaries of at least some of the conductive structures of the stack structure at the steps of the forward staircase structure and the additional steps of the reverse staircase structure, and are each integral and continuous with one of the conductive structures. Memory devices, electronic systems, and methods of forming microelectronic devices are also described.

Embodiments of 3D memory devices and methods for forming the same are disclosed. In an example, a 3D memory device includes a substrate, a peripheral circuit on the substrate, a memory stack including interleaved conductive layers and dielectric layers above the peripheral circuit, an N-type doped semiconductor layer above the memory stack, a plurality of channel structures each extending vertically through the memory stack into the N-type doped semiconductor layer, and a source contact above the memory stack and in contact with the N-type doped semiconductor layer. An upper end of each of the plurality of channel structures is flush with or below a top surface of the N-type doped semiconductor layer.

A semiconductor memory device includes a first substrate including opposite first and second surfaces, a mold structure including gate electrodes stacked on the first surface of the first substrate, a channel structure through the mold structure, a first contact via penetrating the first substrate, a second substrate including opposite third and fourth surfaces, a circuit element on the third surface of the second substrate, a first through-via through the mold structure connecting the first contact via and the circuit element, the first through-via including a first conductive pattern, and a first spacer separating the first conductive pattern from the mold structure, and a second through-via through the mold structure and spaced apart from the first through-via, the second through-via including a second conductive pattern, and a second spacer separating the second conductive pattern from the first substrate and the mold structure.

A memory device, and a method of manufacturing the same, includes a source layer over which a cell region and a peripheral circuit region are defined, memory blocks formed on the source layer in the cell region, and a slit formed between the memory blocks. The memory device also includes a resistor formed in the source layer in the peripheral circuit region, contacts formed on the resistor, and metal lines formed on the contacts and connected to a peripheral circuit.

A method of forming a three-dimensional memory device includes forming an alternating stack of insulating layers and sacrificial material layers over a substrate, forming a memory opening extending through the alternating stack, forming a sacrificial memory opening fill structure in the memory opening, replacing the sacrificial material layers with electrically conductive layers, removing the sacrificial memory opening fill structure selective to the electrically conductive layers, and forming a memory opening fill structure the memory opening after replacing the sacrificial material layers with electrically conductive layers and after removing the sacrificial memory opening fill structure. The memory opening fill structure includes a memory film and a vertical semiconductor channel.

An integrated circuit memory includes a first memory block and an adjacent second memory block. The first memory block comprises a first memory pillar around which a first memory cell is formed. The second memory block comprises a second memory pillar around which a second memory cell is formed. An isolation or slit area between the first and second memory blocks electrically isolates the first and second memory blocks. In an example, the slit area comprising a slit pillar around which no memory cells are formed. The slit pillar is a dummy pillar, and insulator material electrically isolates the slit pillar from a Word Line (WL) through which it passes. The isolation layer electrically can also isolate a (WL) of the first memory block from a corresponding WL of the second memory block. In an example, the slit pillar and the memory pillars have at least in part similar structures.

A microelectronic device comprises a stack structure, a stadium structure within the stack structure, and conductive contact structures. The stack structure comprises a vertically alternating sequence of conductive structures and insulative structures arranged in tiers. Each of the tiers comprises one of the conductive structures and one of the insulative structures. The stadium structure comprises a forward staircase structure having steps comprising edges of the tiers, and a reverse staircase structure opposing the forward staircase structure and having additional steps comprising additional edges of the tiers. The conductive contact structures vertically extend to upper vertical boundaries of at least some of the conductive structures of the stack structure at the steps of the forward staircase structure and the additional steps of the reverse staircase structure, and are each integral and continuous with one of the conductive structures. Memory devices, electronic systems, and methods of forming microelectronic devices are also described.

A three-dimensional (3D) semiconductor memory device including: first and second semiconductor layers horizontally spaced apart from each other; a buried insulating layer between the first and second semiconductor layers; a first cell array structure disposed on the first semiconductor layer, and a second cell array structure disposed on the second semiconductor layer; and an isolation structure disposed on the buried insulating layer between the first and second cell array structures, wherein the first cell array structure includes: an electrode structure including electrodes, which are stacked in a direction perpendicular to a top surface of the first semiconductor layer; and a first source structure disposed between the first semiconductor layer and the electrode structure, the first source structure is extended onto the buried insulating layer, and the isolation structure is between the first source structure of the first cell array structure and a second source structure of the second cell array structure.