SiC Ingot Facet Structure for Stable Laser Processing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The presence of facets in SiC ingots with different resistivity from step-flow growth regions complicates processing, leading to inefficiencies in laser cutting and increased risk of heterogeneous polymorphs due to unstable crystal growth patterns.
Innovation Solution
A SiC ingot design with controlled facet and step-flow growth regions, featuring inclined surfaces and an inflection point to stabilize processing and reduce heterogeneous polymorphs, is proposed, with specific inclinations and positioning to enhance processing stability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a SiC ingot is produced with conventional crystal growth methods, then facets are formed in the SiC ingot, but the difference in resistivity between the facet and step-flow growth region complicates laser processing and reduces throughput
Solution Approach 1:
The patent applies local quality by creating a specific inclined surface structure at the facet boundary region. The inner boundary includes a first inclined surface and a second inclined surface with different inclination angles, where the inflection point is positioned toward the first end. This localized structural modification makes the facet region similar to the step-flow growth region, reducing resistivity differences and enabling uniform laser processing across the entire ingot surface, thereby maintaining high processing throughput while preserving crystal quality
Solution Approach 2:
The patent applies preliminary action by pre-forming the inclined surface structure during the crystal growth process itself. The specific configuration of the inner boundary with controlled inclination angles and inflection point positioning is established in advance during ingot production. This preliminary structural preparation ensures that subsequent laser processing can be performed uniformly across the entire surface without requiring real-time adjustments, thus improving processing efficiency while maintaining crystal quality
2Ease of manufacture
If the facet is made small in the early stages of growth, then processing is simplified, but threading screw dislocations cannot be sufficiently introduced and heterogeneous polymorphs occur
Solution Approach 1:
The patent applies parameter changes by controlling the geometric parameters of the facet inner boundary. The first inclined surface has a smaller inclination angle (5-15 degrees) compared to the second inclined surface (15-30 degrees), and the inflection point is positioned at a specific location toward the first end. These parameter optimizations allow the facet to be sufficiently large to introduce threading screw dislocations and prevent heterogeneous polymorphs, while the inclined surface structure simultaneously simplifies processing by reducing resistivity differences
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 solution results in improved crystal quality and processing ease, reducing processing time and minimizing heterogeneous polymorphs, thereby enhancing production efficiency and substrate quality.
Implementation Method 1
A SiC ingot is obtained by performing crystal growth of a SiC single crystal on a seed crystal
Data Source
AI summary
This SiC ingot includes a step-flow growth region and a facet, in a cut surface that passes through a center and is in a <11-20> direction, an inner boundary between the facet and the step-flow growth region has a first inclined surface inclined in a [−1-120] direction with respect to a crystal growth direction and a second inclined surface inclined in a [11-20] direction with respect to the crystal growth direction, and an inflection point between the first inclined surface and the second inclined surface is located on a side of a first end, which is a Si plane or a plane inclined by an offset angle from the Si plane, from a center position of an ingot length.