Methods, systems, and devices for sequential voltage control for a memory device are described. A memory device may have various voltage sources that support different voltage levels used in various operations of the memory device. Voltage sources of a memory device may be disabled under some circumstances, such as when the memory device is idled, or operated in a low-power or powered-down mode, among other circumstances. In accordance with examples as disclosed herein, voltage sources of a memory device or memory die may be sequentially enabled or sequentially disabled. For example, voltage sources may be enabled in an order from voltage sources having relatively higher nominal voltages to voltage sources having relatively lower voltages, or disabled in an order from voltage sources having relatively lower nominal voltages to voltage sources having relatively higher voltages.

An erasable programmable non-volatile memory includes a first select transistor, a first floating gate transistor, a second select transistor and a second floating gate transistor. A select gate and a first source/drain terminal of the first select transistor receive a first select gate voltage and a first source line voltage, respectively. A first source/drain terminal and a second source/drain terminal of the first floating gate transistor are connected with a second source/drain terminal of the first select transistor and a first bit line voltage, respectively. A select gate and a first source/drain terminal of the second select transistor receive a second select gate voltage and a second source line voltage, respectively. A first source/drain terminal and a second source/drain terminal of the second floating gate transistor are connected with the second source/drain terminal of the second select transistor and a second bit line voltage, respectively.

The present disclosure includes apparatuses, methods, and systems for preventing parasitic current during program operations in memory. An embodiment includes a sense line, an access line, and a memory cell. The memory cell includes a first transistor having a floating gate and a control gate, wherein the control gate of the first transistor is coupled to the access line, and a second transistor having a control gate, wherein the control gate of the second transistor is coupled to the access line, a first node of the second transistor is coupled to the sense line, and a second node of the second transistor is coupled to the floating gate of the first transistor. The memory cell also includes a diode, or other rectifying element, coupled to the sense line and a node of the first transistor.

A memory device includes a first well, a second well, a first active area, a second active area, a third active area, a first poly layer and a second poly layer. The first well is of a first conductivity type. The second well is of a second conductivity type different from the first conductivity type. The first active area is of the second conductivity type and is formed on the first well. The second active area is of the first conductivity type and is formed on the first well and between the first active area and the second well. The third active area is of the first conductivity type and is formed on the second well. The first poly layer is formed above the first well and the second well. The second poly layer is formed above the first well.

Semiconductor device, memory arrays, and methods of forming a memory cell include or utilize one or more memory cells. The memory cell(s) include a first nanosheet transistor connected to a first terminal, a second nanosheet transistor located on top of the first nanosheet transistor and connected in parallel to the first nanosheet transistor and connected to a second terminal, where the first and second nanosheet transistors share a common floating gate and a common output terminal, and an access transistor connected in series to the common output terminal and a low voltage terminal, the access transistor configured to trigger hot-carrier injection to the common floating gate to change a voltage of the common floating gate.

The present disclosure includes apparatuses, methods, and systems for preventing parasitic current during program operations in memory. An embodiment includes a sense line, an access line, and a memory cell. The memory cell includes a first transistor having a floating gate and a control gate, wherein the control gate of the first transistor is coupled to the access line, and a second transistor having a control gate, wherein the control gate of the second transistor is coupled to the access line, a first node of the second transistor is coupled to the sense line, and a second node of the second transistor is coupled to the floating gate of the first transistor. The memory cell also includes a diode, or other rectifying element, coupled to the sense line and a node of the first transistor.

A nonvolatile semiconductor memory device comprises a cell unit including a first and a second selection gate transistor and a memory string provided between the first and second selection gate transistors and composed of a plurality of serially connected electrically erasable programmable memory cells operative to store effective data; and a data write circuit operative to write data into the memory cell, wherein the number of program stages for at least one of memory cells on both ends of the memory string is lower than the number of program stages for other memory cells, and the data write circuit executes the first stage program to the memory cell having the number of program stages lower than the number of program stages for the other memory cells after the first stage program to the other memory cells.

A non-volatile memory combines a data cell and a reference cell. The data cell includes a coupling structure and a transistor stack. The transistor stack is electrically coupled to the coupling structure. The data cell can store data and output a data signal that corresponds to the data. The reference cell includes a transistor stack that has the same structure as that of the data cell and outputs a reference signal. A column circuit is electrically coupled to the data cell and the first reference cell and configured to process the data signal using the reference signal.

A semiconductor device includes a memory cell formed on a semiconductor substrate. The memory cell includes a first source region and a first drain region that are formed in the semiconductor substrate and a first selection gate, and a first floating gate disposed in series between the first source region and the first drain region. A first floating gate transistor including the first drain region and the first floating gate has a threshold set lower than a threshold of a first selection gate transistor including the first source region and the first selection gate.

Techniques are provided for pre-charging NAND strings during a programming operation. The NAND strings are in a block that is divided into vertical sub-blocks. During a pre-charge phase of a programming operation, an overdrive voltage is applied to some memory cells and a bypass voltage is applied to other memory cells. The overdrive voltage allows the channel of an unselected NAND string to adequately charge during the pre-charge phase. Adequate charging of the channel helps the channel voltage to boost to a sufficient level to inhibit programming of an unselected memory cell during a program phase. Thus, program disturb is prevented, or at least reduced. The technique allows, for example, programming of memory cells in a middle vertical sub-block without causing program disturb of memory cells that are not to receive programming.