Graphene Device Fabrication via Trench Pre-Patterning

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Solution Overview

Problem

Current methods for fabricating graphene devices lack control over device dimensions and structures due to the difficulty in handling graphene layers and the limitations imposed by processing temperatures.

Innovation Solution

A process involving pre-patterning device structures and electrodes within trenches in a substrate before graphene deposition, allowing for improved control over device dimensions and structures, and using a protective layer to safeguard the graphene layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If graphene layer is grown or deposited first and then device structures are patterned by etching, then graphene-based devices can be fabricated, but control over device dimensions and structures is poor

Engineering Contradiction:

Improvecontrol over device dimensions and structuresVSAvoiddifficulty of handling graphene layer

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Device structures and electrodes are pre-patterned within trenches in the substrate before graphene deposition. This preliminary structuring allows precise dimensional control of the device features before the graphene layer is added, eliminating the need to etch through the delicate graphene layer afterward.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The conventional sequence is inverted: instead of depositing graphene first and then patterning, the patent patterns the device structures first in trenches, then deposits graphene over the pre-formed structures. This reversal enables better dimensional control while simplifying graphene handling.

Inventive Principle:

Principle #13The other way round (Inversion)

2Temperature

If conventional fabrication processes are used with graphene layer, then graphene devices can be formed, but processing temperature is limited by graphene stability

Engineering Contradiction:

Improveprocessing temperatureVSAvoidstability of graphene layer

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

All temperature-sensitive device structures (electrodes, gate dielectric, gate metal) are pre-formed in the trenches before graphene deposition. This allows subsequent high-temperature processing steps to be performed on the device structures without exposing the graphene layer to temperatures that would compromise its stability.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If graphene layer is handled directly during fabrication, then device can be assembled, but variety and complexity of device structures are limited

Engineering Contradiction:

Improvevariety and complexity of device structuresVSAvoidease of handling graphene layer

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

Device structures are pre-patterned in trenches with precise dimensional control before graphene deposition. This approach enables complex device geometries and varied structures without requiring complex manipulation of the graphene layer itself, thereby increasing design versatility while maintaining ease of operation.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7858989B2Device and process of forming device with device structure formed in trench and graphene layer formed thereover

Publication Date: 2010.12.28 GLOBALFOUNDRIES US INC

AI summary

A graphene-based device is formed with a substrate having a trench therein, a device structure on the substrate and within the trench, a graphene layer over the device structure, and a protective layer over the graphene layer. Fabrication techniques include forming a trench in a substrate, forming a device structure within the trench, forming a graphene layer over the device structure, and forming a protective layer over the graphene layer.