Memory Matrix With Vertical Transistors

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Solution Overview

Problem

Existing memory matrices aim to minimize the average area per bit, but there is a desire to further reduce this ratio while maintaining efficient data storage and access.

Innovation Solution

The proposed electronic circuit design incorporates vertical transistors with two resistive memory elements per access transistor, sharing a single control electrode, and utilizes distinct voltages on second row conductors to minimize power consumption and area requirements, allowing for independent information storage with minimal area penalty.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If vertical transistors are used with two resistive memory elements per access transistor, then the average area per bit is reduced, but the device complexity increases

Engineering Contradiction:
Improveaverage area per bitVSAvoiddevice complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

Two resistive memory elements are combined under a single access transistor, sharing the same control electrode. This merging approach allows both memory elements to be accessed through one transistor, reducing the overall area per bit while the shared control mechanism manages the increased device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The access transistor serves multiple functions by controlling access to two different resistive memory elements. This multi-functionality is achieved through selective voltage application to different row conductors, allowing one transistor to efficiently manage multiple storage elements without proportionally increasing control circuit complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Use of energy by moving object

If distinct voltages are applied to second row conductors during access, then power consumption is reduced, but the control circuit complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcontrol circuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

Different voltage levels are applied to different second row conductors based on their specific function during access operations. Selected row conductors receive one voltage level while unselected rows receive different voltage levels, creating localized voltage conditions that minimize parasitic currents and reduce overall power consumption

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The control circuit implements periodic voltage switching to row conductors during access operations. By applying distinct voltages in a controlled sequence - first to selected rows, then to unselected rows - the system minimizes simultaneous current paths and reduces power consumption while managing control complexity through time-multiplexed voltage application

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 design effectively reduces the average area per bit while maintaining efficient data storage and access, achieving power savings through optimized voltage application and resistive memory element usage.

Implementation Method 1

A phase change material is provided on top of the body. The resistance of the material phase change material depends on the waveform applied during a last write action.

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

The cell is read by measuring the resistance between the column conductors when the row conductor of a selected row is driven so that the access transistors in a selected row become conductive.

Methodology Applied
Scientific EffectField effect transistor conduction: Conduction (electrical)

Data Source

PatentEP1961010B1An electronic circuit with a memory matrix
Publication Date: 2013.05.15 NXP BV
  • EP1961010B1 patent drawingFigure 1~2
  • EP1961010B1 patent drawingFigure 3a~3b
  • EP1961010B1 patent drawingFigure 4~5

AI summary

An electronic circuit comprises a memory matrix (60) with rows and columns of memory cells (16). First row conductors (10, 12) are provided for each of the rows. Second row conductors (12) are provided for successively overlapping pairs of adjacent rows. Column conductors (14) are provided for each of the columns. Each of the memory cells (16) comprises an access transistor (160), a node (166) and a first and second resistive memory element (162, 164). The access transistor (160) is preferably a vertical transistor having a control electrode coupled to the first row conductor (10) of the row of the memory cell (16), a main current channel coupled between the column conductor (14) for the column of the memory cell (160) and the node (166). The first and second resistive memory element (162, 164) are coupled between the node (166) and the second row conductors (12) for the pairs of rows to which the memory cell belongs.