Polycrystalline Diamond Interlayer for CVD Substrate Contamination
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Solution Overview
Problem
Existing methods for synthesizing single crystal CVD diamonds face challenges with uniformity and yield due to temperature variations, impurity uptake, and contamination from carrier substrates, leading to non-uniform crystal morphology, growth rate, and cracking issues.
Innovation Solution
A method involving a carrier substrate coated with a polycrystalline CVD diamond layer, where single crystal diamond substrates are bonded to this layer, allowing for better thermal management and preventing contamination, with the polycrystalline layer being removable to yield individual single crystal diamonds with improved uniformity and ease of extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If single crystal diamond substrates are bonded directly to a refractory metal carrier substrate, then thermal contact is improved, but contamination of the diamond material occurs from the carrier substrate
Solution Approach 1:
A polycrystalline diamond layer is introduced as an intermediary between the refractory metal carrier substrate and the single crystal diamond substrates. This intermediate layer serves dual functions: it provides thermal management by conducting heat away from the growing diamonds, and it prevents contamination by acting as a barrier that stops material from the carrier substrate from etching and incorporating into the single crystal diamond material during CVD growth.
2Productivity
If multiple single crystal diamond substrates are placed on a carrier substrate for batch synthesis, then productivity increases, but uniformity of crystal growth deteriorates due to temperature variations
Solution Approach 1:
The polycrystalline diamond layer acts as a thermal intermediary that distributes heat uniformly across all single crystal diamond substrates in the batch. This intermediate layer ensures that temperature variations across the carrier substrate do not directly affect the growing crystals, thereby maintaining uniform crystal morphology, growth rate, and impurity distribution while enabling batch production of multiple diamonds.
Solution Approach 2:
The invention changes the thermal parameters at the growth surface by introducing the polycrystalline diamond layer, which has superior thermal conductivity compared to the refractory metal carrier. This parameter change stabilizes the temperature distribution across all substrates during batch synthesis, ensuring uniform growth conditions for all single crystal diamonds produced in parallel.
3Temperature
If a thick polycrystalline CVD diamond layer is grown on the carrier substrate, then thermal management is improved, but the layer becomes difficult to remove after diamond growth
Solution Approach 1:
The invention uses a thin polycrystalline diamond film rather than a thick layer. This thin film (sufficient to provide thermal management but not excessively thick) provides the necessary thermal conductivity to manage heat during growth while remaining easy to remove after the single crystal diamonds are formed. The thin film can be cleanly separated from the carrier substrate without requiring excessive force or complex removal 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
The approach results in highly uniform single crystal CVD diamonds with enhanced thermal management and reduced contamination, enabling higher yields and easier product extraction, while allowing for reuse of the carrier substrate.
Implementation Method 1
bonding a plurality of single crystal diamond substrates to the layer of polycrystalline CVD diamond material on the carrier substrate... enabling enhanced thermal management
Implementation Method 2
growing single crystal CVD diamond material on the plurality of single crystal diamond substrates... CVD processes for synthesis of diamond material are now well known in the art
Data Source
Figure 1(a)~1(g)
AI summary
A method of fabricating a plurality of single crystal CVD diamonds, the method comprising: coating a carrier substrate with a layer of polycrystalline CVD diamond material; bonding a plurality of single crystal diamond substrates to the layer of polycrystalline CVD diamond material on the carrier substrate; growing single crystal CVD diamond material on the plurality of single crystal diamond substrates to form a plurality of single crystal CVD diamonds; and separating the plurality of single crystal CVD diamonds from the layer of polycrystalline CVD diamond material on the carrier substrate and any polycrystalline CVD diamond material which has grown between the plurality of single crystal CVD diamonds to yield a plurality of individual single crystal CVD diamonds.