Nitride Semiconductor Electron Blocking Layer Polarization Management
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Solution Overview
Problem
Nitride semiconductor devices face reduced luminous efficiency and increased operating voltage due to the influence of polarization caused by energy level differences in the electron blocking layer.
Innovation Solution
A nitride semiconductor device with an electron blocking layer composed of alternately stacked first and second nitride layers, where the first layers have a higher band gap energy and are formed with a composition like AlxInyGa(1-x-y)N, with energy levels bent at inclinations that decrease closer to the p-type nitride semiconductor layer, minimizing the net polarization charge difference and reducing energy level inclinations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional electron blocking layer is used, then the device structure is simple, but the luminous efficiency is reduced and operating voltage is increased due to polarization effects
Solution Approach 1:
The electron blocking layer is divided into multiple alternating layers of different nitride materials (e.g., AlGaN and InGaN) with different band gap energies. This segmentation allows the total energy level difference to be distributed across multiple interfaces, reducing the polarization effect at each interface while maintaining the overall electron blocking function.
Solution Approach 2:
Different regions of the electron blocking layer have different material compositions and band gap energies. The first nitride layers have higher band gap energy than the second nitride layers, creating local variations in energy levels that optimize electron blocking while reducing polarization. The inclination of energy levels is specifically designed to decrease closer to the p-type nitride semiconductor layer.
2Ease of manufacture
If a conventional electron blocking layer is used, then the device structure is simple, but the operating voltage is increased due to reduced hole concentration
Solution Approach 1:
The electron blocking layer is segmented into multiple alternating layers that collectively manage carrier transport. This segmentation allows for optimized hole injection while maintaining electron blocking, resulting in lower operating voltage compared to a conventional single-layer structure.
Solution Approach 2:
The electron blocking layer uses a composite structure of different nitride materials (e.g., AlGaN and InGaN) with complementary properties. The combination of materials with different band gap energies creates favorable energy band alignment that reduces operating voltage while maintaining effective electron blocking.
3Reliability
If the energy level difference in the electron blocking layer is large, then electron blocking efficiency is improved, but polarization effects increase reducing luminous efficiency
Solution Approach 1:
The total energy level difference required for effective electron blocking is segmented across multiple interfaces between alternating layers. This distribution reduces the polarization effect at each individual interface while maintaining the cumulative electron blocking efficiency needed for device 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
This configuration enhances luminous efficiency and reduces operating voltage by minimizing the impact of polarization, leading to improved electron blocking efficiency and reduced leakage current.
Implementation Method 1
minimizing the entire difference in energy level of an electron blocking layer to reduce the influence caused by polarization
Implementation Method 2
having a plurality of first nitride layers formed of a material having a higher band gap energy than the quantum barrier layers and a plurality of second nitride layers formed of a material having a lower band gap energy than the first nitride layers
Data Source
AI summary
There is provided a nitride semiconductor device. A nitride semiconductor device according to an aspect of the invention may include: an n-type nitride semiconductor layer; a p-type nitride semiconductor layer; an active layer provided between the n-type and p-type nitride semiconductor layers and having quantum well layers and quantum barrier layers alternately stacked on each other; and an electron blocking layer provided between the active layer and the p-type nitride semiconductor layer, and having a plurality of first nitride layers formed of a material having a higher band gap energy than the quantum barrier layers and a plurality of second nitride layers formed of a material having a lower band gap energy than the first nitride layers, the first and second nitride layers alternately stacked on each other to form a stacked structure, wherein the plurality of first nitride layers have energy levels bent at predetermined inclinations, and with greater proximity to the p-type nitride semiconductor layer, the first nitride layers have a smaller inclination of the energy level.