Group III Nitride Semiconductor Light-Emitting Device Flat Layer Formation
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Solution Overview
Problem
In Group III nitride semiconductor light-emitting devices with uneven sapphire substrates, the high concentration of raw material gases on inclined surfaces leads to non-uniform semiconductor growth, causing crystallinity issues and difficulty in achieving a flat surface, which hampers light extraction efficiency.
Innovation Solution
A method is developed to control the partial pressure ratio of raw material gases to suppress semiconductor growth on inclined surfaces, forming a flat semiconductor layer by adjusting the supply amount of gases containing Group V elements, ensuring the growth primarily occurs on the flat surfaces of the sapphire substrate, thereby maintaining a stable growth mode and improving crystallinity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an uneven sapphire substrate is used to improve light extraction efficiency, then light scattering and extraction efficiency are improved, but raw material gas concentration becomes non-uniform causing poor manufacturing precision
Solution Approach 1:
The patent applies local quality by adjusting the partial pressure ratio of raw material gases specifically for regions with different surface orientations. The control method distinguishes between inclined surfaces and flat surfaces, supplying different gas concentration ratios to each region to achieve uniform semiconductor layer growth across the entire uneven substrate while maintaining the light extraction benefits of the uneven structure.
2Illumination intensity
If the pitch width of adjacent mesas is reduced to improve light extraction efficiency, then light scattering is enhanced, but the difficulty of achieving a flat surface increases
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the partial pressure ratio of raw material gases based on the local surface orientation and mesa pitch. By changing the gas supply parameters (partial pressure ratios) in response to the specific geometric conditions, the method achieves uniform semiconductor layer growth even when the pitch width is reduced to enhance light extraction efficiency.
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 approach results in a Group III nitride semiconductor light-emitting device with enhanced light extraction efficiency and improved crystal quality by preventing excessive growth on uneven surfaces, allowing for a flat semiconductor layer formation on sapphire substrates with uneven shapes.
Implementation Method 1
a semiconductor layer formation step of growing a semiconductor layer formed of Group III nitride semiconductor on the low-temperature buffer layer... by supplying at least two types of gases: a raw material gas containing a Group III element and a raw material gas containing a Group V element
Data Source
AI summary
The present invention provides a Group III nitride semiconductor light-emitting device in which a flat semiconductor layer is grown on a sapphire substrate provided with an uneven shape, and a method for producing the same. When the area ratio R of the flat surface area S on the main surface to the total area K of the sapphire substrate is 0.1 or more to less than 0.5, in formation of the semiconductor layer on the sapphire substrate having an uneven shape on the main surface thereof, at least two types of gases: a raw material gas containing a Group III element and a raw material gas containing Group V element are supplied so as to satisfy the equation 1,000≦Y/(2×R)≦1,200. In the equation, Y is the partial pressure ratio of the raw material gas containing Group V element to the raw material gas containing Group III element.