Embodiments of three-dimensional (3D) memory devices having a shielding layer and methods for forming the 3D memory devices are disclosed. In an example, a method for forming a 3D memory device is disclosed. A peripheral device is formed on a substrate. A first interconnect layer including a first plurality of interconnects is formed above the peripheral device. A shielding layer including a conduction region is formed above the first interconnect layer. A second interconnect layer including a second plurality of interconnects is formed above the shielding layer. The conduction region of the shielding layer covers an area of the first and second plurality of interconnects in the first and second interconnect layers. A plurality of memory strings each extending vertically above the second interconnect layer are formed.

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, a first semiconductor layer above the memory stack, a second semiconductor layer above and in contact with the first semiconductor layer, a plurality of channel structures each extending vertically through the memory stack and the first semiconductor layer, and an insulating structure extending vertically through the memory stack, the first semiconductor layer, and the second semiconductor layer.

A semiconductor device may include a plurality of first contact structures, plug-shaped second contact structures configured to be connected to a first number of the plurality of first contact structures, respectively, a slit-shaped second contact structure configured to be connected to a second number of the plurality of first contact structures, adjacent in a first direction, and a third contact structure configured to be connected to sidewalls of the plug-shaped second contact structures, adjacent in the first direction.

A memory die includes an alternating stack of insulating layers and electrically conductive layers, memory stack structures extending through the alternating stack, and each of the memory stack structures includes a respective vertical semiconductor channel and a respective memory film, drain regions located at a first end of a respective one of the vertical semiconductor channels, and a source layer having a first surface and a second surface. The first surface is located at a second end of each of the vertical semiconductor channels, and a semiconductor wafer is not located over the second surface of the source layer.

A three-dimensional semiconductor memory device may include a source structure on a substrate, a stack structure including electrode layers and inter-electrode insulating layers, which are on the source structure and are alternately stacked, a vertical structure penetrating the stack structure and the source structure and being adjacent to the substrate, and a separation insulation pattern penetrating the stack structure and the source structure and being spaced apart from the vertical structure. The uppermost one of the inter-electrode insulating layers may include a first impurity injection region located at a first height from a top surface of the substrate. The stack structure may define a groove, in which the separation insulation pattern is located. An inner sidewall of the groove may define a recess region, which is located at the first height from the top surface of the substrate and is recessed toward the vertical structure.

A semiconductor memory device includes a semiconductor substrate including an upper surface extending in a horizontal direction, a source structure including a trench extending in the horizontal direction, the source structure disposed above the semiconductor substrate, a metal structure in the trench of the source structure and connecting the source structure to the semiconductor substrate, and memory cell strings disposed on both sides of the trench and connected to the source structure.

A semiconductor device includes a first structure including a substrate, circuit devices, a lower interconnection structure electrically connected to the circuit devices, and a second structure on the first structure. The second structure includes a conductive plate layer; gate electrodes on the conductive plate layer and extending in a first direction; separation regions penetrating through the gate electrodes and extending in the first direction; channel structures penetrating through the gate electrodes and respectively including a channel layer; through-contact plugs spaced apart from the gate electrodes and extending in the vertical direction to be electrically connected to the lower interconnection structure of the first structure; first and second contacts electrically connected to the channel layer and the through-contact plugs, respectively; bitlines electrically connecting at least one of each of the first and second contacts to each other; and dummy contacts connected to the bitlines and spaced apart from the through-contact plugs.

In certain aspects, a memory device includes an array of memory cells, a plurality of word lines coupled to the array of memory cells, and a plurality of peripheral circuits coupled to the array of memory cells and configured to control the array of memory cells. A first peripheral circuit of the plurality of peripheral circuits includes a first three-dimensional (3D) transistor coupled to the array of memory cells through at least one of the plurality of word lines. The first 3D transistor includes a 3D semiconductor body, and a gate structure in contact with a plurality of sides of the 3D semiconductor body. The gate structure includes a gate dielectric and a gate electrode.

In certain aspects, a memory device includes an array of memory cells and a plurality of peripheral circuits coupled to the array of memory cells and configured to control the array of memory cells. A first peripheral circuit of the plurality of peripheral circuits includes a first three-dimensional (3D) transistor. The first 3D transistor includes a 3D semiconductor body, and a gate structure in contact with a plurality of sides of the 3D semiconductor body. The gate structure includes a gate dielectric and a gate electrode. The gate electrode includes a metal, and the gate dielectric has a thickness between 1.8 nm and 10 nm.

In certain aspects, a memory device includes an array of memory cells, a plurality of word lines coupled to the array of memory cells, and a plurality of peripheral circuits coupled to the array of memory cells and configured to control the array of memory cells. A first peripheral circuit of the plurality of peripheral circuits includes a first three-dimensional (3D) transistor coupled to the array of memory cells through at least one of the plurality of bit lines. The first 3D transistor includes a 3D semiconductor body, and a gate structure in contact with a plurality of sides of the 3D semiconductor body. The gate structure includes a gate dielectric and a gate electrode.