Diamond Membrane Fabrication via Amorphous Dielectric Seeding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for fabricating diamond membranes are not robust, reproducible, or scalable for industrial use, and often require delicate handling, metal layers that can cause contamination, or aggressive etching processes, making them unsuitable for large-scale industrial applications and CMOS technology compatibility.
Innovation Solution
A method involving a substrate with an amorphous dielectric layer having an isoelectric point of less than 7, where diamond nanoparticles are seeded and grown into a diamond layer, and the substrate is partially removed to form a free-standing diamond membrane, allowing for area-selective growth and avoiding the use of metals, enabling robust, reproducible, and scalable production compatible with CMOS technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods (microwave plasma CVD on silicon nitride membranes) are used to fabricate diamond membranes, then diamond coating can be achieved, but the process requires delicate handling, is not robust, and is not suitable for large industrial scale
Solution Approach 1:
The invention extracts and removes the problematic silicon nitride membrane substrate from the process, growing diamond nanoparticles directly on a silicon wafer. This eliminates the need for delicate handling of pre-fabricated membranes while maintaining the ability to produce high-quality diamond structures suitable for industrial scaling.
Solution Approach 2:
The invention performs preliminary patterning of the silicon substrate with sacrificial material before diamond growth. This allows the diamond nanoparticles to be grown in a controlled manner directly on the substrate, eliminating the need for subsequent membrane transfer and assembly steps, thereby improving both robustness and scalability.
2Manufacturing precision
If metal layers are used for lithographic patterning to define pores, then pore definition can be achieved, but metal contamination occurs in CMOS processes
Solution Approach 1:
The invention uses a sacrificial material layer (such as silicon dioxide or silicon nitride) that is deposited, patterned, and then completely removed after serving its purpose of defining the pore locations during diamond growth. This disposable sacrificial layer approach achieves precise pore definition without introducing metal contamination into the CMOS process.
Solution Approach 2:
The sacrificial material acts as an intermediary between the lithographic pattern and the final diamond structure. It temporarily defines the pore locations during the growth process and is then removed, leaving clean pores in the diamond membrane without requiring metal layers that would contaminate CMOS devices.
3Ease of manufacture
If aggressive etch processing steps are used to create nanopores, then pore formation can be achieved, but the process becomes complex and expensive requiring specialized tools
Solution Approach 1:
The diamond nanoparticles self-organize and grow in a controlled manner during the CVD process, with the porous structure forming naturally as part of the growth mechanism rather than requiring subsequent aggressive etching steps. This self-organizing growth process reduces processing complexity and eliminates the need for specialized etching tools, making the process more suitable for industrial manufacturing.
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 method allows for the fabrication of both porous and non-porous diamond membranes with well-defined pores over large areas, ensuring robustness, reproducibility, and scalability, while being cost-effective and compatible with CMOS processes, suitable for a wide range of applications including bio-compatible and conductive membranes.
Implementation Method 1
seeding diamond nanoparticles onto the exposed surface
Implementation Method 2
growing a diamond layer from the seeded diamond nanoparticles
Data Source
Figure 1~2
Figure 3~3e
Figure 4~4b
AI summary
In a first aspect, the present invention relates to a method for forming a diamond membrane (410), comprising: a. providing a substrate (100) having an amorphous dielectric layer (200) thereon, the amorphous dielectric layer (200) comprising an exposed surface (220), the exposed surface (220) having an isoelectric point of less than 7, preferably at most 6; b. seeding diamond nanoparticles (300) onto the exposed surface (220); c. growing a diamond layer (400) from the seeded diamond nanoparticles (300); and d. removing a portion (600) of the substrate (100) from underneath the diamond layer (400), the removed portion (600) extending at least up to the amorphous dielectric layer (200), thereby forming the diamond membrane (410) over the removed portion (600).