2D Material Transfer Cleanup via Sacrificial Layer Infiltration
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Solution Overview
Problem
Existing methods for transferring 2D materials to target substrates often leave residual organic sacrificial materials, such as PMMA, which can impair the performance and integration of these materials in semiconductor devices.
Innovation Solution
A method involving infiltration of the residual organic sacrificial material with a metal or ceramic material, followed by thermal, plasma, or UV treatment to remove the sacrificial material without damaging the 2D material, and optionally using the infiltrated material as a protection or passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional transfer methods using organic sacrificial material are used, then the 2D material can be transferred to the target substrate, but residual organic material remains on the 2D material surface
Solution Approach 1:
The patent introduces an inorganic sacrificial material (such as aluminum oxide or silicon oxide) as an intermediary substance during the transfer process. This inorganic material serves as a temporary mediator that facilitates the transfer of 2D materials to the target substrate while being completely removable without leaving organic residues. The inorganic sacrificial material is deposited via atomic layer deposition (ALD) and can be cleanly removed through wet etching or other selective removal techniques, thus resolving the contradiction between successful transfer and surface cleanliness.
2Manufacturing precision
If thermal treatment is applied to remove organic residue, then the organic material can be removed, but the 2D material may be damaged
Solution Approach 1:
The patent changes the chemical composition parameter of the sacrificial material from organic to inorganic. Inorganic materials like aluminum oxide or silicon oxide have different thermal stability characteristics compared to organic materials. They can be removed at lower temperatures through chemical etching processes, thereby avoiding the high-temperature thermal treatment that would damage the sensitive 2D material. This parameter change resolves the contradiction by enabling complete removal without compromising material integrity.
Solution Approach 2:
The patent replaces thermal removal mechanisms with chemical removal mechanisms. Instead of using high-temperature thermal treatment to remove the sacrificial material, the invention employs chemical etchants that selectively dissolve or react with the inorganic sacrificial material at much lower temperatures. This substitution of the removal mechanism allows complete elimination of the sacrificial material while preserving the 2D material's structural integrity.
3Ease of manufacture
If the organic sacrificial material is used for transfer, then the transfer process is simple, but complete removal of the sacrificial material is difficult
Solution Approach 1:
The patent changes the chemical composition parameter of the sacrificial material from organic to inorganic. Inorganic materials such as aluminum oxide or silicon oxide offer distinct advantages: they can be deposited through well-established ALD processes and removed through selective wet etching using common chemicals like phosphoric acid or hydrofluoric acid. This parameter change maintains process simplicity while enabling complete and clean removal without the stubborn residues that plague organic sacrificial materials.
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 method effectively removes the organic sacrificial material completely, preserving the integrity of the 2D material and enabling its seamless integration into various applications, including semiconductor devices, while allowing for the formation of a dielectric layer.
Implementation Method 1
infiltrating the organic sacrificial material with a metal or ceramic material
Implementation Method 2
thermal, plasma, or UV treatment to remove the sacrificial material
Implementation Method 3
thermal, plasma, or UV treatment to remove the sacrificial material
Implementation Method 4
thermal, plasma, or UV treatment to remove the sacrificial material
Data Source
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AI summary
In a first aspect, the present invention relates to a method for removing an organic sacrificial material (301) from a 2D material (200), comprising: (a) providing a target substrate (120) having thereon the 2D material (200) and a layer of the organic sacrificial material (301) over the 2D material (200), (b) infiltrating the organic sacrificial material (301) with a metal or ceramic material (311), and (c) removing the organic sacrificial material (301).