Stacked 2D Material Layers With Solvent-Free Clean Interface Transfer
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Solution Overview
Problem
Conventional methods for forming stacked heterostructures using two-dimensional materials often result in residual contamination and material deterioration due to the use of chemical solvents and wet etching processes, leading to deteriorated device performance.
Innovation Solution
A method is developed to cleanly peel off two-dimensional material building blocks from target substrates without using etchants or solvents, allowing for vertical stack-by-stack heterostructure transfer and maintaining pristine interlayer interfaces by utilizing supporting films and low-melting metal layers to ensure clean interfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If chemical solvents and wet etching processes are used to form stacked heterostructures, then the transfer process can be completed, but residual contamination and material deterioration occur leading to deteriorated device performance
Solution Approach 1:
The patent extracts and removes the harmful chemical solvents and etchants from the transfer process. Instead of using chemical methods, the invention employs a mechanical peeling approach where the stacked heterostructure is transferred by peeling it off from the sacrificial substrate, thereby eliminating the source of residual contamination and material deterioration.
Solution Approach 2:
The patent introduces a sacrificial substrate as an intermediary medium that enables the transfer process without direct chemical contact between the heterostructure and the final substrate. The heterostructure is first grown on the sacrificial substrate, then peeled off and transferred to the target substrate, allowing the use of a benign intermediate medium instead of harmful chemicals.
2Productivity
If conventional transfer methods are used, then material can be transferred, but intrinsic properties of two-dimensional materials are compromised due to residual contamination
Solution Approach 1:
The patent extracts and eliminates the contaminating agents (chemical solvents and etchants) from the transfer process. By using a mechanical peeling method on a sacrificial substrate, the process achieves material transfer while preserving the intrinsic properties of two-dimensional materials without exposure to harmful chemicals.
Solution Approach 2:
The stacked heterostructure itself serves the dual function of being both the material to be transferred and the peeling interface. The van der Waals heterostructure can be peeled off from the sacrificial substrate due to the weak interfacial bonding, allowing the material to transfer itself without requiring additional chemical processing steps that would compromise its properties.
3Ease of manufacture
If stacked heterostructures are formed using conventional methods, then device fabrication can proceed, but device performance deteriorates due to material degradation
Solution Approach 1:
The patent removes the harmful chemical processing steps from the device fabrication workflow. By extracting the chemical solvents and etchants and replacing them with a mechanical peeling process on a sacrificial substrate, the method enables device fabrication while preventing material degradation and preserving device performance.
Solution Approach 2:
The patent performs the heterostructure assembly and transfer preparation in advance on a sacrificial substrate before final device fabrication. The stacked heterostructure is completely formed and prepared for transfer beforehand, allowing the actual device fabrication to proceed with clean, pre-prepared materials that have not been exposed to degrading chemical processes.
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 enables the fabrication of semiconductor structures with maintained intrinsic properties and ultraclean interfaces, achieving cubic integration and improving device performance by eliminating residual contamination and material degradation.
Implementation Method 1
A method is developed to cleanly peel off two-dimensional material building blocks from target substrates without using etchants or solvents, allowing for vertical stack-by-stack heterostructure transfer
Implementation Method 2
utilizing supporting films and low-melting metal layers to ensure clean interfaces
Data Source
AI summary
A semiconductor structure includes a semiconductor substrate, a plurality of stacked units, a conductive structure, a plurality of dielectrics, a first electrode strip, a second electrode strip, and a plurality of contact structures. The stacked units are stacked up over the semiconductor substrate, and comprises a first passivation layer, a second passivation layer and a channel layer sandwiched between the first passivation layer and the second passivation layer. The conductive structure is disposed on the semiconductor substrate and wrapping around the stacked units. The dielectrics are surrounding the stacked units and separating the stacked units from the conductive structure. The first electrode strip and the second electrode strip are located on two opposing sides of the conductive structure. The contact structures are connecting the channel layer of each of the stacked units to the first electrode strip and the second electrode strip.