This patent document provides implementations and examples of circuits and devices based on low-energy consumption semiconductor structures exhibiting multi-valued states. In one aspect, a semiconductor device is configured to comprise: a multi-layer structure forming a magnetoelectric or multiferroic system to include a ferromagnetic, magnetostrictive layer that exhibits a biaxial magnetic anisotropy and an underlying metal structure exhibits a spin Hall effect to provide a conversion between electrical energy and magnetic energy with more than two distinctive magnetic states.

Methods, systems, and devices for drive strength calibration for multi-level signaling are described. A driver may be configured to have an initial drive strength and to drive an output pin of a transmitting device toward an intermediate voltage level of a multi-level modulation scheme, where the output pin is coupled with a receiving device via a channel. The receiving device may generate, and the transmitting device may receive, a feedback signal indicating a relationship between the resulting voltage of the channel and an value for the intermediate voltage level. The transmitting device may determine and configure the driver to use an adjusted drive strength for the intermediate voltage level based on the feedback signal. The driver may be calibrated (e.g., independently) for each intermediate voltage level of the multi-level modulation scheme. Further, the driver may be calibrated for the associated channel.

Disclosed is a threshold voltage-programmable field effect transistor-based (e.g., a ferro-electric field effect transistor (FeFET)-based) memory circuit employing source-line and/or bit-line-applied variable programming assist voltages. For single-bit data storage in a FeFET, decremental programming assist voltages are selectively applied by a voltage driver to the source-line and/or the bit-line connected to a FeFET during repeat programming processes when previous attempts at programming have failed. For multi-bit data storage in a FeFET, different programming assist voltages are associated with different multi-bit data values and at least one specific programming assist voltage is applied by a voltage driver to the source-line and/or the bit-line connected to a selected FeFET during a programming process to achieve storage of a specific multi-bit data value. Optionally, multiple FeFETs in the same row can be currently programmed with different multi-bit data values. Optionally, different decremental programming assist voltages are applied if/when repeat programming processes are required.

A memory device includes a plurality of memory cells. Each memory cell includes a multi-gate FeFET that has a first source/drain terminal, a second source/drain terminal, and a gate with a plurality of ferroelectric layers configured such that each of the ferroelectric layers has a respective unique switching E-field.

A high-density low voltage ferroelectric (or paraelectric) memory bit-cell that includes a planar ferroelectric or paraelectric capacitor. The memory bit-cell comprises 1T1C configuration, where a plate-line is parallel to a word-line, or the plate-line is parallel to a bit-line. The memory bit-cell can be 1TnC, where ‘n’ is a number. In a 1TnC bit-cell, the capacitors are vertically stacked allowing for multiple values to be stored in a single bit-cell. The memory bit-cell can be multi-element FE gain bit-cell. In a multi-element FE gain bit-cell, data sensing is done with signal amplified by a gain transistor in the bit-cell. As such, higher storage density is realized using multi-element FE gain bit-cells. In some examples, the 1T1C, 1TnC, and multi-element FE gain bit-cells are multi-level bit-cells. To realize multi-level bit-cells, the capacitor is placed in a partially switched polarization state by applying different voltage levels or different time pulse widths at the same voltage level.

Techniques, systems, and devices for time-resolved access of memory cells in a memory array are described herein. During a sense portion of a read operation, a selected memory cell may be charged to a predetermined voltage level. A logic state stored on the selected memory cell may be identified based on a duration between the beginning of the charging and when selected memory cell reaches the predetermined voltage level. In some examples, time-varying signals may be used to indicate the logic state based on the duration of the charging. In some examples, the duration of the charging may be based on a polarization state of the selected memory cell, a dielectric charge state of the selected state, or both a polarization state and a dielectric charge state of the selected memory cell.

Systems and methods disclosed herein are related to a memory system. In one aspect, the memory system includes a first set of memory cells including a first string of memory cells and a second string of memory cells; and a first switch including: a first electrode connected to first electrodes of the first string of memory cells and first electrodes of the second string of memory cells, and a second electrode connected to a first global bit line, wherein gate electrodes of the first string of memory cells are connected to a first word line and gate electrodes of the second string of memory cells are connected to a second word line.

Methods, systems, and devices for multi-level receivers with various operating modes (e.g., on-die termination mode, termination-off mode, etc.) are described. Different modes may be utilized for receiving different types of signaling over a channel. Each mode may correspond to the use of a respective set of receivers configured for the different types of signaling. For example, a device may include a first set of receivers used to receive a first type of signal (e.g., with the channel being actively terminated) and a second set of receivers used to receive a second type of signal (e.g., with the channel being non-terminated). When communicating with another device, based on the type of signaling used for communications, either the first set of receivers or the second set of receivers may be enabled (e.g., through selecting a receiver path for the corresponding mode).

Methods, systems, and devices for enhanced data reliability in multi-level memory cells are described. For a write operation, a host device may identify a first set of data to be stored by a set of memory cells at a memory device. Based on a quantity of bits within the first set of data being less than a storage capacity of the set of memory cells, the host device may generate a second set of data and transmit a write command including the first and second sets of data to the memory device. For a read operation, the host device may receive a first set of data from the memory device in response to transmitting a read command. The memory device may extract a second set of data from the first set of data and validate a portion of the first set of data using the second set of data.

Methods, systems, techniques, and devices for operating a ferroelectric memory cell or cells are described. A first ferroelectric memory cell may be used to charge a second ferroelectric memory cell by transferring charge from a plate of first ferroelectric memory cell to a plate of the second ferroelectric memory cell. In some examples, prior to the transfer of charge, the first ferroelectric memory cell may be selected for a first operation in which the first ferroelectric memory cell transitions from a charged state to a discharged state and the second ferroelectric memory cell may be selected for a second operation during which the second ferroelectric memory cell transitions from a discharged state to a charged state. The discharging of the first ferroelectric memory cell may be used to assist in charging the second ferroelectric memory cell.