Embodiments of three-dimensional (3D) memory devices having through array contacts (TACs) and methods for forming the same are disclosed. In an example, a 3D memory device includes a substrate, a memory stack on the substrate comprising a plurality of conductor/dielectric layer pairs, a channel structure extending vertically through the conductor/dielectric layer pairs in the memory stack, a TAC extending vertically through the conductor/dielectric layer pairs in the memory stack, and a dummy channel structure filled with a dielectric layer and extending vertically through the conductor/dielectric layer pairs in the memory stack.

A semiconductor memory device includes a semiconductor substrate, a select gate on the semiconductor substrate, a control gate disposed adjacent to the select gate and having a first sidewall and a second sidewall, and a charge storage layer between the control gate and the semiconductor substrate. The control gate includes a third sidewall close to the second sidewall of the select gate, a fourth sidewall opposite to the third sidewall, and a non-planar top surface between the third sidewall and the fourth sidewall. The non-planar top surface includes a first surface region that descends from the third sidewall to the fourth sidewall. The charge storage layer extends to the second sidewall of the select gate.

A semiconductor device includes a non-volatile memory. The non-volatile memory includes a first dielectric layer disposed on a substrate, a floating gate disposed on the dielectric layer, a control gate, a second dielectric layer disposed between the floating gate and the control gate and having one of a silicon oxide layer, a silicon nitride layer and multilayers of silicon oxide and silicon nitride, and an erase gate and a select gate. The erase gate and the select gate include a stack of a bottom polysilicon layer and an upper metal layer.

A control gate electrode and a memory gate electrode of a memory cell of a non-volatile memory are formed in a memory cell region of a semiconductor substrate, and a dummy gate electrode is formed in a peripheral circuit region. Then, n.sup.+-type semiconductor regions for a source or a drain of the memory cell are formed in the memory cell region and n.sup.+-type semiconductor regions for a source or a drain of MISFET are formed in the peripheral circuit region. Then, a metal silicide layer is formed over the n.sup.+-type semiconductor regions but the metal silicide layer is not formed over the control gate electrode, the memory gate electrode, and the gate electrode. Subsequently, the gate electrode is removed and replaced with the gate electrode for MISFET, Then, after removing the gate electrode and replacing it with a gate electrode for MISFET, a metal silicide layer is formed over the memory gate electrode and the control gate electrode.

According to an embodiment, a non-volatile memory device includes a first conductive layer, electrodes, an interconnection layer and at least one semiconductor layer. The electrodes are arranged between the first conductive layer and the interconnection layer in a first direction perpendicular to the first conductive layer. The interconnection layer includes a first interconnection and a second interconnection. The semiconductor layer extends through the electrodes in the first direction, and is electrically connected to the first conductive layer and the first interconnection. The device further includes a memory film between each of the electrodes and the semiconductor layer, and a conductive body extending in the first direction. The conductive body electrically connects the first conductive layer and the second interconnection, and includes a first portion and a second portion connected to the second interconnection.

The second portion has a width wider than the first portion.

First and second wells are formed in a semiconductor substrate. First and second trenches in the first second wells, respectively, each extend vertically and include a central conductor insulated by a first insulating layer. A second insulating layer is formed on a top surface of the semiconductor substrate. The second insulating layer is selectively thinned over the second trench. A polysilicon layer is deposited on the second insulating layer and then lithographically patterned to form: a first polysilicon portion over the first well that is electrically connected to the central conductor of the first trench to form a first capacitor plate, a second capacitor plate formed by the first well; and a second polysilicon portion over the second well forming a floating gate electrode of a floating gate transistor of a memory cell having an access transistor whose control gate is formed by the central conductor of the second trench.

Various embodiments of the present application are directed towards an integrated memory chip with an enhanced device-region layout for reduced leakage current and an enlarged word-line etch process window (e.g., enhanced word-line etch resiliency). In some embodiments, the integrated memory chip comprises a substrate, a control gate, a word line, and an isolation structure. The substrate comprises a first source/drain region. The control gate and the word line are on the substrate. The word line is between and borders the first source/drain region and the control gate and is elongated along a length of the word line. The isolation structure extends into the substrate and has a first isolation-structure sidewall. The first isolation-structure sidewall extends laterally along the length of the word line and underlies the word line.

An integrated circuit includes a first semiconductor well contained in a semiconductor substrate and a second semiconductor well contained in the first semiconductor well. A capacitive element for the integrated circuit includes a first electrode and a second electrode, where the first electrode includes at least one vertical conductive structure filling a trench extending vertically into the first semiconductor well. The vertical conductive structure is electrically isolated from the first semiconductor well by a dielectric envelope covering a base and the sides of the trench. The vertical conductive structure penetrates into the second semiconductor well at least at one longitudinal end of the trench. The second electrode includes the first semiconductor well and the second semiconductor well.

Embodiments of three-dimensional (3D) memory devices having through array contacts (TACs) and methods for forming the same are disclosed. In an example, a method for forming a 3D memory device is disclosed. A dielectric stack including interleaved a plurality of dielectric layers and a plurality of sacrificial layers is formed above a substrate. A channel structure extending vertically through the dielectric stack is formed. A first opening extending vertically through the dielectric stack is formed. A spacer is formed in a plurality of shallow recesses and on a sidewall of the first opening. The plurality of shallow recesses abut the sidewall of the first opening. A TAC extending vertically through the dielectric stack is formed by depositing a conductor layer in contact with the spacer in the first opening. A slit extending vertically through the dielectric stack is formed.

A memory device includes a substrate, a first transistor, a second transistor, and a capacitor. The first transistor is over the substrate and includes a select gate. The second transistor is over the substrate and connected to the first transistor in series, in which the second transistor includes a floating gate. The capacitor is over the substrate and connected to the second transistor, wherein the capacitor includes a top electrode, a bottom electrode in the substrate, and an insulating layer between the top electrode and the bottom electrode. The insulating layer includes nitrogen. A nitrogen concentration of the insulating layer increases in a direction from the top electrode to the bottom electrode.