Patent classifications
G11C11/221
NAND based sequential circuit with ferroelectric or paraelectric material
A low power sequential circuit (e.g., latch) uses a non-linear polar capacitor to retain charge with fewer transistors than traditional CMOS sequential circuits. In one example, a sequential circuit includes pass-gates and inverters, but without a feedback mechanism or memory element. In another example, a sequential uses load capacitors (e.g., capacitors coupled to a storage node and a reference supply). The load capacitors are implemented using ferroelectric material, paraelectric material, or linear dielectric. In one example, a sequential uses minority, majority, or threshold gates with ferroelectric or paraelectric capacitors. In one example, a sequential circuit uses minority, majority, or threshold gates configured as NAND gates.
FERROELECTRIC CAPACITOR INTEGRATED WITH LOGIC
Ferroelectric capacitor is formed by conformably depositing a non-conductive dielectric over the etched first and second electrodes, and forming a metal cap or helmet over a selective part of the non-conductive dielectric, wherein the metal cap conforms to portions of sidewalls of the non-conductive dielectric. The metal cap is formed by applying physical vapor deposition at a grazing angle to selectively deposit a metal mask over the selective part of the non-conductive dielectric. The metal cap can also be formed by applying ion implantation with tuned etch rate. The method further includes isotopically etching the metal cap and the non-conductive dielectric such that non-conductive dielectric remains on sidewalls of the first and second electrodes but not on the third and fourth electrodes.
MEMORY CIRCUIT AND WRITE METHOD
A method of writing data to a memory array of three-terminal memory cells includes simultaneously programming a first subset of memory cells in a first column of the memory array to a first logic level by activating a first select line of the first column and a first bit line of the first column, and simultaneously programming a second subset of memory cells in the first column to the first logic level by activating the first select line and a second bit line of the first column.
READ ALGORITHM FOR MEMORY DEVICE
Methods, systems, and devices for a read algorithm for a memory device are described. When performing a read operation, the memory device may access a memory cell to retrieve a value stored by the memory cell. The memory device may compare a set of reference voltages with a signal output by the memory cell based on accessing the memory cell. Thus, the memory device may determine a set of candidate values stored by the memory cell, where each candidate value is associated with one of the reference voltages. The memory device may determine and output the value stored by the memory cell based on determining the set of candidate values. In some cases, the memory device may determine the value stored by the memory cell based on performing an error control operation on each of the set of candidate values to detect a quantity of errors within each candidate value.
FEEDBACK FOR MULTI-LEVEL SIGNALING IN A MEMORY DEVICE
Methods, systems, and devices for feedback for multi-level signaling in a memory device are described. A receiver may use a modulation scheme to communicate information with a host device. The receiver may include a first circuit, a second circuit, a third circuit, and a fourth circuit. Each of the first circuit, the second circuit, the third circuit, and the fourth circuit may determine, for a respective clock phase, a voltage level of a signal modulated using the modulation scheme. The receiver may include a first feedback circuit, a second feedback circuit, a third feedback circuit, and a fourth feedback circuit. The first feedback circuit that may use information received from the first circuit at the first clock phase and modify the signal input into the second circuit for the second clock phase.
Pillar capacitor and method of fabricating such
The memory bit-cell formed using the ferroelectric capacitor results in a taller and narrower bit-cell compared to traditional memory bit-cells. As such, more bit-cells can be packed in a die resulting in a higher density memory that can operate at lower voltages than traditional memories while providing the much sought after non-volatility behavior. The pillar capacitor includes a plug that assists in fabricating a narrow pillar.
Pulsing scheme for a ferroelectric memory bit-cell to minimize read or write disturb effect and refresh logic
A memory is provided which comprises a capacitor including non-linear polar material. The capacitor may have a first terminal coupled to a node (e.g., a storage node) and a second terminal coupled to a plate-line. The capacitors can be a planar capacitor or non-planar capacitor (also known as pillar capacitor). The memory includes a transistor coupled to the node and a bit-line, wherein the transistor is controllable by a word-line, wherein the plate-line is parallel to the bit-line. The memory includes a refresh circuitry to refresh charge on the capacitor periodically or at a predetermined time. The refresh circuit can utilize one or more of the endurance mechanisms. When the plate-line is parallel to the bit-line, a specific read and write scheme may be used to reduce the disturb voltage for unselected bit-cells. A different scheme is used when the plate-line is parallel to the word-line.
Wear leveling for random access and ferroelectric memory
Methods, systems, and devices related to wear leveling for random access and ferroelectric memory are described. Non-volatile memory devices, e.g., ferroelectric random access memory (FeRAM) may utilize wear leveling to extend life time of the memory devices by avoiding reliability issues due to a limited cycling capability. A wear-leveling pool, or number of cells used for a wear-leveling application, may be expanded by softening or avoiding restrictions on a source page and a destination page within a same section of memory array. In addition, error correction code may be applied when moving data from the source page to the destination page to avoid duplicating errors present in the source page.
Ferroelectric memory cell sensing
Methods, systems, and devices for operating a ferroelectric memory cell or cells are described. A memory device may maintain a digit line voltage at a ground reference for a duration associated with biasing a ferroelectric capacitor of a memory cell. For example, a digit line that is in electronic communication with a ferroelectric capacitor may be virtually grounded while a voltage is applied to a plate of the ferroelectric capacitor, and the ferroelectric capacitor may be isolated from the virtual ground after a threshold associated with applying the voltage to the plate is reached. A switching component (e.g., a transistor) that is in electronic communication with the digit line and virtual ground may be activated to virtually ground the digit line and deactivated to isolate the digit line from virtual ground.
Array data bit inversion
Methods, systems, and apparatuses for memory array bit inversion are described. A memory cell (e.g., a ferroelectric memory cell) may be written with a charge associated with a logic state that may be the inverse of the intended logic state of the cell. That is, the actual logic state of one or more memory cells may be inverted, but the intended logic state of the memory cells may remain unchanged. Different sets of transistors may be configured around a sense component of a cell to enable reading and writing of intended and inverted logic states from or to the cell. For instance, a first set of transistors may be used to read the logic state currently stored at a memory cell, while a second set of transistors may be used to read a logic state inverted from the currently stored logic state.