2T0C Memory Cell with Single Bit Line for Dense Integration

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Solution Overview

Problem

Existing 2T0C-based memory cells require two bit lines and two word lines, making it difficult to reduce the feature size and integrate memory cells effectively.

Innovation Solution

A 2T0C-based memory cell design using a single bit line and two transistors, where data storage and retrieval are controlled by word lines and the bit line voltage, allowing for a parasitic capacitance-based storage mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a conventional 2T0C-based memory cell is configured with two bit lines and two word lines, then data storage and retrieval functions are achieved, but the feature size cannot be reduced and integration density remains low

Engineering Contradiction:
Improvefeature sizeVSAvoidnumber of bit lines and word lines
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates one bit line from the conventional two-bit-line configuration, reducing the number of interconnect lines while maintaining memory functionality through alternative control mechanisms using the remaining bit line in combination with two word lines

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The single bit line is designed to serve multiple functions by combining it with different word lines for both data storage and retrieval operations, allowing the same physical line to participate in different operational modes depending on the active word line configuration

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

2Productivity

If the number of bit lines and word lines is reduced to decrease feature size, then integration density improves, but device functionality may be compromised

Engineering Contradiction:
Improveintegration densityVSAvoiddata storage and retrieval functionality
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent transitions from a two-dimensional configuration with separate bit lines to a three-dimensional control scheme where two word lines and one bit line interact in a stacked manner, effectively using vertical stacking to compensate for the reduced number of horizontal interconnect lines

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The word lines are used to pre-configure the transistor states and prepare the memory cell for subsequent data operations through the single bit line, enabling functionality to be achieved through preparatory control actions rather than through multiple simultaneous bit lines

Inventive Principle:
Principle #10Preliminary 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

The design achieves a smaller feature size of 12F^2 per bit, enabling the memory cell to be stacked in multiple layers, thereby improving integration density without increasing physical space.

Implementation Method 1

a 2T0C-based memory cell may store data by using a parasitic capacitance formed by the two transistors

Methodology Applied
Scientific EffectParasitic capacitance: Parasitic Capacitance

Data Source

PatentEP4597500A12t0c-based memory cell and operating method thereof
Publication Date: 2025.08.06 UI (UNIVERSITY IND FOUNDATION) YONSEI UNIVERSITY
  • EP4597500A1 patent drawingFigure 1
  • EP4597500A1 patent drawingFigure 2
  • EP4597500A1 patent drawingFigure 3

AI summary

The present disclosure relates to a 2T0C-based memory cell. The 2T0C-based memory cell includes a first transistor and a second transistor connected through a storage node, a first word line connected to the first transistor and controlling an on/off state of the first transistor through an operation of applying a voltage, a second word line connected to the second transistor and controlling an on/off state of the second transistor such that data stored in the memory cell are read, and a single bit line connected to the first transistor and the second transistor and allowing the storage node to be charged or discharged depending on a voltage applied to the single bit line.