Domain Switching Layer for Sub-60 mV/dec Logic Switching

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Solution Overview

Problem

The scaling down of silicon-based transistors is limited by high power density and the inability to lower operating voltage below 0.8 V, due to a subthreshold swing (SS) value of about 60 mV/dec, which restricts further device miniaturization.

Innovation Solution

A logic switching device utilizing a combination of ferroelectric and anti-ferroelectric materials with different crystalline phases and doping concentrations, integrated in a domain switching layer to achieve a negative capacitance effect, reducing the subthreshold swing and enhancing control efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If silicon-based transistors are scaled down, then device miniaturization is achieved, but power density increases and operating voltage cannot be lowered below 0.8 V

Engineering Contradiction:
Improvedevice sizeVSAvoidpower density
Core Design Contradiction:
Volume of moving objectVSPower

Solution Approach 1:

The patent changes the fundamental parameter of subthreshold swing from the conventional 60 mV/dec limit to below 60 mV/dec by introducing a negative capacitance effect through a domain switching layer. This parameter change enables operating voltages below 0.8 V while maintaining device functionality, thereby resolving the contradiction between device scaling and power density control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite domain switching layer comprising both ferroelectric and anti-ferroelectric materials with different crystalline phases (orthorhombic and tetragonal). This composite structure generates the negative capacitance effect that enables sub-60 mV/dec subthreshold swing, allowing transistor scaling without excessive power density increase.

Inventive Principle:
Principle #40Composite materials

2Use of energy by stationary object

If operating voltage is lowered to enable scaling, then power consumption decreases, but subthreshold swing limit of 60 mV/dec prevents voltage reduction below 0.8 V

Engineering Contradiction:
Improvepower consumptionVSAvoidoperating voltage control
Core Design Contradiction:
Use of energy by stationary objectVSEase of operation

Solution Approach 1:

The patent fundamentally changes the subthreshold swing parameter from the thermionic emission-limited 60 mV/dec to below 60 mV/dec through negative capacitance. This parameter transformation enables operating voltages below 0.8 V while maintaining adequate on/off current ratios, thus reducing power consumption without sacrificing voltage control capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the conventional thermionic emission mechanism that limits subthreshold swing with a electrostatic field-effect mechanism enhanced by negative capacitance. This substitution of the underlying physical mechanism enables breakthrough below the 60 mV/dec barrier, allowing lower operating voltages and reduced power consumption.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If conventional silicon-based transistors are used, then manufacturing maturity is maintained, but subthreshold swing cannot be reduced below 60 mV/dec

Engineering Contradiction:
Improvemanufacturing maturityVSAvoidsubthreshold swing control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent uses a composite domain switching layer with ferroelectric and anti-ferroelectric materials that can be integrated into existing CMOS manufacturing processes. The specific combination of materials with different crystalline phases enables sub-60 mV/dec subthreshold swing while maintaining compatibility with standard semiconductor fabrication techniques, thus achieving improved manufacturing precision without sacrificing manufacturing maturity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent introduces the domain switching layer as a localized functional component between the gate electrode and channel, rather than requiring fundamental changes to the entire transistor structure. This local quality enhancement approach allows sub-60 mV/dec performance to be achieved in specific regions while maintaining overall manufacturing process compatibility and maturity.

Inventive Principle:
Principle #3Local quality

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 solution effectively lowers the subthreshold swing below 60 mV/dec, enabling more efficient voltage amplification and improved switching characteristics, thereby facilitating the scaling down of transistors and enhancing device performance.

Implementation Method 1

A logic switching device utilizing a combination of ferroelectric and anti-ferroelectric materials with different crystalline phases and doping concentrations, integrated in a domain switching layer to achieve a negative capacitance effect, reducing the subthreshold swing and enhancing control efficiency.

Methodology Applied
Scientific EffectNegative capacitance effect: Capacitance

Data Source

PatentEP3614440B1Logic switching device and method of manufacturing the same
Publication Date: 2025.01.01 SAMSUNG ELECTRONICS CO LTD
  • EP3614440B1 patent drawingFigure 1~3
  • EP3614440B1 patent drawingFigure 4~6
  • EP3614440B1 patent drawingFigure 7~8

AI summary

Provided are a logic switching device and a method of manufacturing the same. The logic switching device may include a domain switching layer adjacent to a gate electrode. The domain switching layer may include a ferroelectric material region and an anti-ferroelectric material region. The domain switching layer may be a non-memory element. The logic switching device may include a channel, a source and a drain both connected to the channel, the gate electrode arranged to face the channel, and the domain switching layer provided between the channel and the gate electrode.