Graphene Contact Structures for Low-Resistance 2D IC Interfaces

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Solution Overview

Problem

The scaling of features in integrated circuits faces challenges due to high contact resistance when contacting two-dimensional (2D) materials, particularly as silicon fails below 7nm, and existing solutions do not effectively address this issue.

Innovation Solution

The use of graphene layers to provide superior contacts to 2D transition metal dichalcogenide (TMD) layers, where graphene is grown on conductors with TMD layers contacting the substrate, reducing contact resistance and enabling efficient integration in IC structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional contacts are used to contact 2D materials in integrated circuits, then the manufacturing process is simpler, but contact resistance is high which degrades device performance

Engineering Contradiction:
Improvecontact resistanceVSAvoidcontact structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces an intermediary material layer (such as titanium nitride, tungsten silicide, or graphene) between the conventional metal contact and the 2D material channel. This intermediary layer serves as a mediator that facilitates better electrical contact by matching the electronic properties of both materials, thereby reducing contact resistance without requiring fundamental changes to the overall contact structure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite contact structures consisting of multiple material layers with different properties. For example, a stack of metal layers combined with 2D material layers or transition metal dichalcogenides creates a composite contact that leverages the high conductivity of metals and the low contact resistance properties of 2D materials, achieving superior electrical contact

Inventive Principle:
Principle #40Composite materials

2Productivity

If feature size is scaled down to increase device density, then more devices can be integrated on chip, but contact resistance increases and silicon fails below 7nm

Engineering Contradiction:
Improvedevice densityVSAvoidcontact resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the material parameters and dimensional parameters of the contact structure. By transitioning from bulk 3D materials to 2D materials with atomic thickness, and by optimizing the lateral dimensions of the contact, the patent achieves low contact resistance at scaled dimensions. The 2D material's unique electronic structure parameters enable effective contact at sub-7nm scales where conventional silicon-based contacts fail

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by using 2D materials specifically at the contact interface where low contact resistance is critical, while maintaining conventional structures in other regions. The 2D material is selectively placed only where it is needed to improve contact properties, allowing the rest of the device to continue using established manufacturing processes and materials

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If 2D transition metal dichalcogenide layers are used to contact substrates, then integration is enabled, but contact resistance remains high

Engineering Contradiction:
Improveintegration capabilityVSAvoidcontact resistance
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent makes the 2D material contact structure multi-functional by designing it to simultaneously provide mechanical support, electrical contact, and thermal management. The contact structure is engineered to perform multiple functions: supporting the suspended 2D material channel, providing low-resistance electrical pathway, and dissipating heat from the active device region, thereby improving overall device performance while maintaining ease of integration

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

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 approach significantly reduces contact resistance and enhances the integration of 2D materials in ICs, enabling improved performance and capacity in next-generation technologies by leveraging the properties of graphene and TMDs.

Implementation Method 1

The use of graphene layers to provide superior contacts to 2D transition metal dichalcogenide (TMD) layers, where graphene is grown on conductors with TMD layers contacting the substrate, reducing contact resistance

Methodology Applied
Scientific EffectElectrical Conduction: Conduction (electrical)

Data Source

PatentEP4156299B1Integrated circuit structures with graphene contacts
Publication Date: 2024.07.24 INTEL CORP
  • EP4156299B1 patent drawingFigure 1A~1B
  • EP4156299B1 patent drawingFigure 1C~1E
  • EP4156299B1 patent drawingFigure 2

AI summary

Embodiments of the disclosure are directed to advanced integrated circuit (IC) structure fabrication and, in particular, to IC structures with graphene contacts. Other embodiments may be disclosed or claimed.