Remote Plasma CVD for Nanocrystalline Diamond Deposition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for depositing nanocrystalline diamond films, such as hot filament CVD and microwave CVD, face challenges like metal contamination, high process pressure affecting film uniformity, and ion-induced grain structure disorder, necessitating an improved approach for forming durable and high-hardness diamond layers.
Innovation Solution
A method involving a remote plasma source is used to deposit nanocrystalline diamond films by delivering an activated gas mixture of alkane and hydrogen precursors through different pressure zones, optimizing the radical-to-ionized species ratio to promote sp3 bonding and uniform deposition, with additional hydrogen plasma cleaning to remove polymers and ensure layer quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hot filament CVD is used to deposit nanocrystalline diamond films, then diamond film deposition is achieved, but metal contamination occurs due to precursor gases reacting with the metal filament
Solution Approach 1:
The invention extracts and removes the metal filament from the deposition system by using a remote plasma source instead. The plasma is generated in a separate chamber and transported to the substrate, eliminating the metal component that causes contamination while maintaining the diamond deposition capability
Solution Approach 2:
The invention introduces plasma as an intermediary between the precursor gases and the substrate. The plasma activates the precursor gases to form reactive species that deposit diamond, eliminating the need for direct contact between precursor gases and metal filaments
2Reliability
If microwave CVD is used to deposit nanocrystalline diamond films, then contaminant issues are reduced, but high process pressure affects film uniformity
Solution Approach 1:
The invention segments the deposition process into two distinct stages: a high-pressure plasma generation stage in the remote plasma source that creates reactive species, and a low-pressure deposition stage at the substrate that ensures uniform film formation. This separation allows optimization of each stage independently
Solution Approach 2:
The invention uses plasma as an intermediary to transport reactive species from the high-pressure source region to the low-pressure deposition region, enabling uniform film formation at low pressure while maintaining high plasma density at the source
3Stability of the object's composition
If microwave plasma is used in microwave CVD, then ion energy is reduced, but ions still attack the NCD grain boundary and induce grain structure disorder
Solution Approach 1:
The invention extracts ions from the deposition process by using a remote plasma source that generates primarily radical species rather than ionized species. The plasma is allowed to cool and neutralize before reaching the substrate, removing the harmful ion component while retaining the beneficial radical species for diamond deposition
Solution Approach 2:
The invention converts the harmful high-energy ions into beneficial low-energy radical species by allowing the plasma to cool during transport. The radical species maintain reactivity for diamond formation while losing the damaging high-energy characteristics that cause grain boundary attack
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 achieves high-quality nanocrystalline diamond layers with improved uniformity and reduced contamination, enhancing the durability and performance of the deposited films by preferentially forming sp3 bonds and maintaining film integrity.
Implementation Method 1
activating the deposition gas to create an activated deposition gas, the activated deposition gas having a ratio of radical species to ionized species
Implementation Method 2
The radical species can then be delivered to the substrate to deposit a nanocrystalline diamond layer with preferentially sp3 bonding
Implementation Method 3
delivering a hydrogen containing gas to a remote plasma chamber; activating the hydrogen containing gas to create an activated hydrogen containing gas; and delivering the activated hydrogen containing gas to the substrate in the process volume
Implementation Method 4
delivering the activated deposition gas to a substrate in a process volume... and depositing a nanocrystalline diamond layer on a surface of the substrate
Data Source
AI summary
Methods for making a nanocrystalline diamond layer are disclosed herein. A method of forming a layer can include activating a deposition gas comprising an alkane and a hydrogen containing gas at a first pressure, delivering the activated deposition gas to the substrate at a second pressure which is less than the first pressure, forming a nanocrystalline diamond layer, treating the layer with an activated hydrogen containing gas to remove one or more polymers from the surface and repeating the cycle to achieve a desired thickness.