Memcapacitor Cross-Point Memory Cells for Non-Volatile Data Storage

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Dynamic memory cells that store charge in capacitors require frequent refreshing due to charge dissipation, and resistive memory cells in cross-point structures face challenges in maintaining stable resistance states for data representation.

Innovation Solution

The development of memcapacitor devices with statically programmable semiconductive materials and mobile dopants between conductive electrodes, allowing capacitors to maintain distinct capacitance states for months without power, and the use of AC voltage for reading and programming to determine and alter these states effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic memory cells use capacitors to store charge, then data can be stored in two or more states, but charge dissipates over time requiring frequent refreshing

Engineering Contradiction:

Improvedata storage stabilityVSAvoidcharge retention time

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent transitions from dynamic capacitor-based memory to resistive memory cells that maintain stable resistance states. By changing the storage mechanism from charge-based to resistance-based, the system achieves non-volatile storage without refreshing, directly resolving the charge dissipation problem.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention replaces the electrical charge storage mechanism (capacitor) with a resistive state mechanism. This substitution eliminates the need for periodic refreshing while maintaining data representation through two or more stable states.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If resistive memory cells are arranged in cross-point structures, then data can be stored in high and low resistance states, but maintaining stable resistance states for data representation is challenging

Engineering Contradiction:

Improveresistance state stabilityVSAvoidcross-point structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the memory array into distinct word lines and bit lines that cross to form memory cells. Each intersection represents an independent memory cell, allowing selective access through row and column decoders, which simplifies the control of complex cross-point structures.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces selection circuitry including word line and bit line decoders as intermediaries between the control logic and the cross-point memory cells. These intermediaries enable precise selection of individual cells or groups of cells, managing the complexity of the cross-point architecture.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If AC voltage is used for reading and programming memory cells, then capacitance states can be determined and altered, but the process requires precise voltage control

Engineering Contradiction:

Improvecapacitance state detectionVSAvoidvoltage control complexity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The patent employs AC voltage signals with specific frequencies and waveforms for reading and programming operations. The periodic nature of these signals enables precise control over the timing and duration of voltage application, allowing accurate determination and alteration of capacitance states through controlled cycles.

Inventive Principle:

Principle #19Periodic action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables non-volatile memory cells to maintain programmed capacitance states for extended periods, allowing for reliable data storage and retrieval without frequent refreshing, and allows for efficient programming and reading of data in cross-point memory arrays.

Implementation Method 1

capacitors to maintain distinct capacitance states for months without power

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

memcapacitor devices with statically programmable semiconductive materials and mobile dopants between conductive electrodes

Methodology Applied

Scientific EffectMobile dopants: Dopants

Implementation Method 3

the use of AC voltage for reading and programming to determine and alter these states effectively

Methodology Applied

Scientific EffectAC voltage: Electric Field

Data Source

PatentUS10796744B2Cross-point memory cells, non-volatile memory arrays, methods of reading a memory cell, methods of programming a memory cell, methods of writing to and reading from a memory cell, and computer systems

Publication Date: 2020.10.06 MICRON TECHNOLOGY INC

AI summary

Cross-point memory cells, non-volatile memory arrays, methods of reading a memory cell, methods of programming a memory cell, and methods of writing to and reading from a memory cell are described. In one embodiment, a cross-point memory cell includes a word line extending in a first direction, a bit line extending in a second direction different from the first direction, the bit line and the word line crossing without physically contacting each other, and a capacitor formed between the word line and the bit line where such cross. The capacitor comprises a dielectric material configured to prevent DC current from flowing from the word line to the bit line and from the bit line to the word line.