Graded Impurity Semiconductor Layer for Light Emitting Elements
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Solution Overview
Problem
Semiconductor light emitting elements face challenges due to lattice constant differences between substrates and semiconductor layers, leading to issues like crystal defects, wafer warpage, and reduced luminous efficiency.
Innovation Solution
A material layer stack is designed with a substrate having a first lattice constant and a semiconductor layer with a second lattice constant, comprising impurity layers with varying impurity concentrations and thicknesses to optimize electrical characteristics, including a first impurity layer closest to the substrate, a second layer with higher impurity concentration, and a third layer with the highest concentration contacting the active layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a semiconductor layer with a different lattice constant is grown on a substrate, then light emission functionality is achieved, but crystal defects and wafer warpage occur
Solution Approach 1:
The semiconductor layer is divided into multiple impurity layers (first, second, and third impurity layers) with progressively increasing impurity concentrations. This segmentation allows gradual lattice constant adjustment from the substrate interface toward the active layer, reducing sudden lattice mismatch and minimizing crystal defects while maintaining light emission functionality.
Solution Approach 2:
The impurity concentration is systematically changed across different layers, with the first impurity layer having a lower concentration, the second having a medium concentration, and the third having the highest concentration. This parameter gradient approach enables progressive lattice constant adjustment, harmonizing the lattice mismatch between substrate and semiconductor layer while preserving functional performance.
2Power
If impurity concentration is increased to improve electrical conductivity, then operation voltage decreases, but leakage current increases
Solution Approach 1:
Different impurity concentrations are applied to different regions (layers) of the semiconductor structure. The first impurity layer near the substrate has lower concentration to minimize leakage, while the third impurity layer near the active layer has higher concentration to reduce operation voltage. This local quality differentiation allows simultaneous optimization of both parameters in different regions.
Solution Approach 2:
The solution transitions from a single-layer uniform impurity distribution to a multi-layer graded impurity distribution. By adding the dimensional aspect of layering, the patent creates a vertical concentration gradient that enables independent optimization of electrical conductivity and leakage current control in different vertical zones of the semiconductor layer.
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 a light emitting element with low leakage current, low operation voltage, and excellent luminous efficiency by carefully managing impurity concentrations and thicknesses in the impurity layers, improving crystallinity and electrical conductivity.
Implementation Method 1
a first impurity layer having a first impurity concentration; a second impurity layer having a second impurity concentration that is greater than the first impurity concentration; and a third impurity layer having a third impurity concentration that is greater than the second impurity concentration
Implementation Method 2
Semiconductor light emitting elements are semiconductor devices capable of generating light of various colors by recombination of electrons and holes in a junction area
Data Source
AI summary
Disclosed herein are a material layer stack, a light emitting element, a light emitting package, and a method of fabricating a light emitting element. The material layer stack includes: a substrate having a first lattice constant; and a semiconductor layer grown on the substrate, the semiconductor layer having a second lattice constant that is different from the first lattice constant. Using the material layer stack, a light emitting element having a low leakage current, a low operation voltage, and an excellent luminous efficiency can be obtained.