RAMO4 Substrate Grooves for Nitride Crystal Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing group III nitride crystals using RAMO4 substrates face challenges in achieving sufficient separation without damaging the crystal, leading to unsatisfactory quality due to residual stress and difficulty in reusing the substrate.
Innovation Solution
A RAMO4 substrate with a monocrystalline structure and a principal surface featuring a plurality of grooves and an off-angle θ, where tan θ ≤ Wy/Wx, is used to facilitate controlled cleavage and reduce residual stress during the separation process, ensuring the quality of the group III nitride crystal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional RAMO4 substrate is used for growing group III nitride crystals, then the substrate can be cleaved to separate the crystal, but the separation is insufficient and causes damage to the crystal quality
Solution Approach 1:
The substrate surface is segmented into multiple regions with different off-angles. Specifically, the substrate includes a first region with a first off-angle and a second region with a second off-angle that is larger than the first off-angle. This segmentation allows different areas to serve different functions: the first region provides stable crystal growth while the second region facilitates easy separation, thus resolving the contradiction between crystal quality and separation ease.
Solution Approach 2:
Different regions of the substrate are given different local properties through varying off-angles. The first region has a smaller off-angle optimized for high-quality crystal growth, while the second region has a larger off-angle optimized for easy cleavage and separation. This local differentiation allows the substrate to simultaneously achieve both high crystal quality and easy separation without compromising either aspect.
2Ease of operation
If the substrate cleavability is increased to facilitate separation, then separation becomes easier, but residual stress and warping increase reducing crystal quality
Solution Approach 1:
The substrate is divided into regions with different off-angles to separate the functions of crystal growth and separation. The first region with smaller off-angle maintains low residual stress for high-quality crystal growth, while the second region with larger off-angle provides enhanced cleavability for easy separation. This functional segmentation resolves the contradiction between separation ease and crystal quality.
Solution Approach 2:
The off-angle parameter is varied across different regions of the substrate. By changing the off-angle from a smaller value in the first region to a larger value in the second region, the substrate optimizes both crystal growth quality and separation ease in different areas, thereby resolving the contradiction between these two requirements.
3Device complexity
If a single off-angle is used for the substrate, then the structure is simpler, but the substrate cannot be easily reused after crystal separation
Solution Approach 1:
The substrate structure is segmented into multiple regions with different off-angles. The first region with smaller off-angle is optimized for maintaining substrate integrity and enabling reuse, while the second region with larger off-angle facilitates complete crystal separation. This segmentation allows the substrate to be reused efficiently without compromising structural simplicity too much.
Solution Approach 2:
Different local regions of the substrate are optimized for different functions: the first region prioritizes substrate reusability through smaller off-angle, while the second region prioritizes separation efficiency through larger off-angle. This local optimization enables substrate reuse while maintaining reasonable structural complexity.
Data Source
AI summary
An RAMO4 substrate that includes an RAMO4 monocrystalline substrate formed of a single crystal represented by general formula RAMO4, wherein R represents one or more trivalent elements selected from the group consisting of Sc, In, Y, and lanthanoid elements, A represents one or more trivalent elements selected from the group consisting of Fe(III), Ga, and Al, and M represents one or more divalent elements selected from the group consisting of Mg, Mn, Fe(II), Co, Cu, Zn, and Cd. The RAMO4 monocrystalline substrate has a principal surface with a plurality of grooves. The principal surface has an off-angle θ with respect to a cleaving surface of the single crystal. The RAMO4 monocrystalline substrate satisfies tan θ≤Wy/Wx, where Wx is the width at the top surface of a raised portion between the grooves, and Wy is the height of the raised portion.