Diamond Layer Transfer via Graphitic Zone Fracture
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Solution Overview
Problem
Existing methods for transferring a useful layer of crystalline diamond onto a support substrate using Smart-Cut technology face challenges such as high annealing temperatures leading to structural defects and increased costs due to multiple implantation and thermal annealing steps, which are detrimental when substrates have different coefficients of thermal expansion.
Innovation Solution
A process involving a single implantation of ionized hydrogen atoms at a specific temperature to form a graphitic planar zone, followed by thermal annealing at a lower temperature to fracture the substrate, reducing the risk of defects and costs by eliminating the need for multiple implantation and annealing steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal annealing is applied at high temperature (>1300°C) to fracture the donor substrate along the damaged zone, then the useful layer can be exposed, but structural defects and cracks are formed due to different coefficients of thermal expansion
Solution Approach 1:
The patent changes the temperature parameter from high (>1300°C) to low (800-1000°C) annealing temperature. This parameter change allows the fracture process to occur at temperatures that do not induce thermal stress damage, resolving the contradiction between achieving useful layer exposure and maintaining structural integrity.
Solution Approach 2:
The patent applies preliminary thermal annealing (800-1000°C) before the final fracture step to pre-treat the damaged zone. This preliminary action prepares the material structure for clean fracture at lower temperatures, preventing defect formation while ensuring complete layer separation.
2Manufacturing precision
If multiple implantation and thermal annealing steps are applied to form graphitic zone and achieve fracture, then the transfer quality is improved, but the operating time and costs increase
Solution Approach 1:
The patent merges the graphitic zone formation and fracture preparation steps into a single low-temperature annealing process (800-1000°C). This consolidation eliminates the need for separate high-temperature treatment steps, reducing total processing time while maintaining transfer quality through the combined effect of the unified thermal process.
Solution Approach 2:
The patent implements a continuous single-step annealing process that simultaneously achieves graphitic zone formation, damaged zone preparation, and fracture initiation. This continuous action eliminates interruptions and repeated heating/cooling cycles, significantly reducing operating time while preserving the quality benefits of thorough material treatment.
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 lowers the risk of structural failure and mechanical stresses, enhances the quality of the transfer process, and reduces operating time and costs by using a single implantation and thermal annealing step, while maintaining the crystalline quality of the useful layer.
Implementation Method 1
implanting gaseous species, comprising ionized hydrogen atoms, through the first surface of the donor substrate
Implementation Method 2
applying thermal annealing to the donor substrate, according to a thermal budget having an annealing temperature of between 800°C and 1000°C, so as to transform the flat zone damaged at the end of step b 02 ) into a graphitic planar zone
Implementation Method 3
applying thermal annealing to the assembly obtained at the end of step e 02 ), according to a thermal budget suitable for fracturing the donor substrate along the graphitic planar zone
Data Source
Figure 1a~1e
Figure 2a~2e
Figure 3a~3e
AI summary
A process for transferring a useful layer (1) onto a support substrate (2), comprising the following successive steps: a) providing a donor substrate (3) made of crystalline diamond; b) implanting gaseous species (4) through the first surface (30) of the donor substrate (3) at a given dose and implantation temperature adapted to form a planar graphitic zone (5); c) assembling the donor substrate (3) to the support substrate (2) by direct adhesion; d) applying thermal annealing with an appropriate thermal budget to fracture the donor substrate (3) along the planar graphitic zone (5); the annealing temperature being greater than or equal to 800°C;the implantation temperature is: above a minimum temperature beyond which bubbling of the implanted gaseous species (4) occurs at the first surface (30) when the donor substrate (3) is subjected, in the absence of a stiffening effect, to thermal annealing according to said thermal budget, below a maximum temperature beyond which the given implantation dose no longer allows the formation of the graphitic plane zone (5).