AlN Single-Crystal Substrate Composition for Crack-Resistant Processing
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Solution Overview
Problem
AlN single-crystal substrates tend to crack during processing such as grinding, polishing, or cutting, leading to reduced yield in manufacturing.
Innovation Solution
An AlN single-crystal substrate is designed to satisfy a specific relation involving thermal conductivities, electrical resistivity, and transmittances, specifically 5≤[(λ25−λ200)×log10 ρ]/(T640-660−T260-280)≤50, where λ25 and λ200 are thermal conductivities, ρ is electrical resistivity, and T640-660 and T260-280 are average transmittances, to minimize cracking during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AlN single-crystal substrates are used for deep ultraviolet light emitting elements, then high ultraviolet transmittance and high thermal conductivity are achieved, but the substrates are likely to crack during processing such as grinding, polishing, or cutting
Solution Approach 1:
The invention changes the physical parameter ranges of the AlN single crystal substrate by specifying precise ranges for thermal conductivity (λ25: 20-30 W/m·K, λ200: 15-25 W/m·K), electrical resistivity (ρ: 1×10^3-1×10^17 Ω·cm), and transmittance characteristics (T640-660: 70-95%, T260-280: 40-70%). These parameter changes optimize the balance between mechanical strength, thermal management, and optical performance, reducing cracking during processing while maintaining high yield
2Reliability
If the thermal conductivity and transmittance are optimized for light emitting performance, then the substrate structure becomes more constrained, making it more prone to cracking
Solution Approach 1:
The invention optimizes the interplay between thermal conductivity parameters (λ25, λ200), electrical resistivity (ρ), and transmittance parameters (T640-660, T260-280) within specific ranges. This coordinated parameter optimization ensures that the substrate maintains both excellent light emitting performance and sufficient mechanical strength to resist cracking during processing
Solution Approach 2:
The invention treats the AlN single crystal substrate as a composite functional material that simultaneously provides thermal conduction, electrical insulation, and optical transmission. By optimizing the combination of these properties within specified parameter ranges, the substrate achieves a balance between optical performance and mechanical robustness
Data Source
AI summary
There is provided an AlN single-crystal substrate satisfying a relation: 5≤[(λ25−λ200)×log10 ρ]/(T640-660−T260-280)≤50, wherein λ25 is a thermal conductivity (W/m·K) at 25° C. of the AlN single-crystal substrate; λ200 is a thermal conductivity (W/m·K) at 200° C. of the AlN single-crystal substrate; ρ is an electrical resistivity (Ω·cm) at 25° C. of the AlN single-crystal substrate; T640-660 is an average value of transmittance (%) at 640 to 660 nm in a transmission spectrum of the AlN single-crystal substrate; and T260-280 is an average value of transmittance (%) at 260 to 280 nm in the transmission spectrum.