LED Chip N-Type Layer Segmentation for Conductivity and Light Absorption
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Solution Overview
Problem
Conventional LED chips, especially micro-LEDs, face issues with light absorption and poor electrical conductivity due to excessively thick n-type semiconductor layers, leading to reduced light output efficiency.
Innovation Solution
The LED chip design includes a p-type semiconductor layer, a light-emitting layer, and an n-type semiconductor layer with a thin ohmic contact layer and metal electrodes, where metal atoms from the electrodes diffuse to form an ohmic contact, reducing the semiconductor layer thickness and enhancing electrical conductivity and light output efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the n-type semiconductor layer thickness is increased to ensure electrical conductivity, then electrical conductivity is improved, but light absorption increases and light output efficiency deteriorates
Solution Approach 1:
The n-type semiconductor layer is segmented into multiple sub-layers (first n-type semiconductor sub-layer, second n-type semiconductor sub-layer, third n-type semiconductor sub-layer) with different thicknesses and doping concentrations. This segmentation allows each sub-layer to perform specialized functions: the first sub-layer provides electrical conductivity, the second sub-layer reduces light absorption, and the third sub-layer serves as an ohmic contact layer, thereby resolving the contradiction between electrical conductivity and light absorption.
Solution Approach 2:
Different regions of the n-type semiconductor layer are assigned different local qualities through varying doping concentrations and thicknesses. The first n-type semiconductor sub-layer has higher doping concentration for electrical conductivity, while the second and third sub-layers have optimized properties to minimize light absorption. This local quality differentiation allows the structure to simultaneously achieve good electrical conductivity and low light absorption.
2Loss of energy
If the n-type semiconductor layer thickness is reduced to reduce light absorption, then light output efficiency is improved, but electrical conductivity deteriorates
Solution Approach 1:
The n-type semiconductor layer is divided into multiple sub-layers where the first sub-layer maintains sufficient thickness and doping concentration for electrical conductivity, while the second and third sub-layers are optimized to reduce light absorption. This segmentation enables the overall structure to achieve low light absorption while maintaining adequate electrical conductivity through the combined effect of different sub-layers.
Solution Approach 2:
The n-type semiconductor layer is constructed as a composite structure with multiple sub-layers having different properties. This composite approach allows the structure to exhibit both low light absorption characteristics (from the optimized thickness and material composition of outer sub-layers) and good electrical conductivity (from the doped first sub-layer), resolving the contradiction between these two requirements.
3Volume of moving object
If the LED chip size is reduced to micro-LED dimensions, then compactness is improved, but light absorption and electrical conductivity problems become more evident
Solution Approach 1:
In micro-LED structures, the n-type semiconductor layer is segmented into multiple thin sub-layers, each with optimized thickness and doping concentration. This segmentation enables the micro-LED to maintain compact dimensions while ensuring that each sub-layer contributes appropriately to electrical conductivity and light emission, preventing excessive light absorption that would otherwise occur in thicker structures.
Solution Approach 2:
The micro-LED structure employs local quality optimization by assigning different doping concentrations and thicknesses to different sub-layers of the n-type semiconductor layer. This allows the compact micro-LED to achieve uniform electrical properties and minimize light absorption across its small volume, resolving the scaling challenges associated with reduced chip size.
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
This design effectively reduces light absorption and improves electrical conductivity, resulting in higher light output efficiency, particularly noticeable in smaller micro-LED sizes, while also simplifying manufacturing and reducing costs for micro-LED displays.
Implementation Method 1
A region of the first n-type semiconductor sub-layer located between the first metal electrode and the ohmic contact layer contains metal atoms diffusing from the first metal electrode
Implementation Method 2
a light-emitting layer, an n-type semiconductor layer... The light-emitting layer is disposed between the p-type semiconductor layer and the n-type semiconductor layer
Data Source
AI summary
A light-emitting diode chip including a p-type semiconductor layer, a light-emitting layer, an n-type semiconductor layer, and a first metal electrode is provided. The light-emitting layer is disposed between the p-type semiconductor layer and the n-type semiconductor layer. The n-type semiconductor layer includes a first n-type semiconductor sub-layer, a second n-type semiconductor sub-layer, and an ohmic contact layer. The ohmic contact layer is disposed between the first n-type semiconductor sub-layer and the second n-type semiconductor sub-layer. The first metal electrode is disposed on the first n-type semiconductor sub-layer. A region of the first n-type semiconductor sub-layer located between the first metal electrode and the ohmic contact layer contains metal atoms diffusing from the first metal electrode, so as to form ohmic contact between the first metal electrode and the ohmic contact layer.