Semiconductor Chip Lateral Flank Sawtooth Out-Coupling
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Solution Overview
Problem
Existing radiation-emitting semiconductor chips face challenges in maximizing light out-coupling efficiency and have complex production processes, particularly in creating structures that enhance lateral light emission.
Innovation Solution
A radiation-emitting semiconductor chip with a transparent carrier, such as sapphire, featuring a sawtooth-shaped out-coupling structure on its lateral flank, which is formed during the singulation process using dry chemical etching, enhances light emission by deflecting radiation and reducing total reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth lateral flank is used in conventional semiconductor chips, then the production process is simple, but light out-coupling efficiency is poor due to total internal reflection
Solution Approach 1:
The out-coupling structures are formed during the singulation process itself, before the chips are fully separated. The singulation traces are intentionally designed to create sawtooth or roughened profiles on the lateral flanks of the carrier, which will later serve as light out-coupling structures. This preliminary structuring eliminates the need for separate post-processing steps to create light-extraction features.
Solution Approach 2:
The patent combines two functions into a single process step: the singulation process simultaneously serves both to separate the semiconductor layer from the carrier and to create the light out-coupling structures on the lateral flanks. By merging the structuring function into the singulation process, the overall device complexity and manufacturing steps are reduced while achieving improved light extraction.
2Loss of energy
If separate structuring steps are added to create light out-coupling structures, then light extraction is improved, but device complexity and manufacturing steps increase
Solution Approach 1:
The out-coupling structures are formed during the singulation process itself, before the chips are fully separated. The singulation traces are intentionally designed to create sawtooth or roughened profiles on the lateral flanks of the carrier, which will later serve as light out-coupling structures. This preliminary structuring eliminates the need for separate post-processing steps to create light-extraction features.
Solution Approach 2:
The patent combines two functions into a single process step: the singulation process simultaneously serves both to separate the semiconductor layer from the carrier and to create the light out-coupling structures on the lateral flanks. By merging the structuring function into the singulation process, the overall device complexity and manufacturing steps are reduced while achieving improved light extraction.
3Loss of energy
If a transparent carrier is used to allow light transmission, then light out-coupling is improved, but the carrier material selection is limited to specific transparent materials
Solution Approach 1:
The patent applies different optical properties to different parts of the system: the carrier is made transparent in the regions where light out-coupling is desired (lateral flanks and radiation exit surface), while the semiconductor layer maintains its light-generating properties. This local optimization allows the carrier to be transparent where needed for light extraction while maintaining structural integrity and compatibility with the semiconductor layer in other regions.
Solution Approach 2:
The patent employs composite material systems where the carrier (such as sapphire, silicon carbide, or gallium nitride) is combined with the semiconductor layer (InGaN, InGaAs, or InGaP). This composite structure allows each material to contribute its optimal properties: the carrier provides mechanical support and transparent light transmission, while the semiconductor layer provides efficient light generation. The interface between these materials is optimized for both structural integrity and optical performance.
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 significantly improves light out-coupling efficiency by directing radiation effectively and simplifies the production process through integrated structuring during singulation, making the semiconductor chip more suitable for optoelectronic components.
Implementation Method 1
The out-coupling structure is suitable for increasing the out-coupling of light from the semiconductor chip, in particular relative to a semiconductor chip having a smooth, unstructured lateral flank... by deflecting radiation within the carrier
Implementation Method 2
The carrier is designed to be transparent for the electromagnetic radiation that is emitted by the epitaxial semiconductor layer sequence during operation... The transmission coefficient here refers to the ratio of transmitted radiation to incident radiation
Implementation Method 3
which is formed during the singulation process using dry chemical etching, enhances light emission by deflecting radiation and reducing total reflection
Data Source
AI summary
Disclosed is a radiation-emitting semi-conductor chip (1) comprising an epitaxial semi-conductor layer sequence (3) which emits electromagnetic radiation in operation. The epitaxial semi-conductor layer sequence (3) is applied on a a transparent substrate (4), wherein the substrate (4) has a first main surface (8) facing the semi-conductor layer sequence (3), a second main surface (9) facing away from the semi-conductor layer sequence (3) and a first lateral flank (10) arranged between the first main surface (8) and the second main surface (9), and the lateral flank (10) has a decoupling structure which is formed in a targeted manner from separating tracks. Also disclosed is a method for producing the semi-conductor chip, and a component comprising such a semi-conductor chip.