Trapezoidal N-Type Layer Geometry for Micro LED Light Extraction
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Solution Overview
Problem
Current semiconductor devices face challenges in achieving high light extraction efficiency, high resolution, increased manufacturing yield, and reduced manufacturing costs, particularly in the production of micro semiconductor display devices.
Innovation Solution
A semiconductor device structure comprising a light-emitting structure with a p-type semiconductor layer, an active layer, and an n-type semiconductor layer, along with specific contact layers and a protection layer, is designed with inclined surfaces and varying widths to enhance light extraction and manufacturing efficiency. The manufacturing method involves forming these layers on a growth substrate, isolating light-emitting structures, and transferring them to a panel using temporary substrates and adhesion layers to achieve a chip scale package form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the semiconductor device uses a conventional structure with vertical layers, then the manufacturing process is simple, but the light extraction efficiency is low
Solution Approach 1:
The patent applies asymmetry by forming the n-type semiconductor layer with a trapezoidal cross-section where the lower surface width is greater than the upper surface width. This asymmetric geometry creates inclined side surfaces that facilitate light extraction while maintaining structural integrity. The asymmetric design allows light to escape more efficiently at specific angles without requiring complex manufacturing processes, thus resolving the contradiction between manufacturing simplicity and light extraction efficiency.
Solution Approach 2:
The patent transitions from a conventional vertical layer structure to a three-dimensional trapezoidal structure by extending the lower surface of the n-type semiconductor layer beyond the upper surface. This dimensional change creates inclined side surfaces that provide additional light extraction pathways in lateral directions, improving light extraction efficiency without significantly complicating the manufacturing process.
2Loss of energy
If the semiconductor device uses a larger size, then the light extraction area is increased, but the resolution of the display device is reduced
Solution Approach 1:
The patent segments the light-emitting structure into distinct functional layers with the n-type semiconductor layer forming a trapezoidal base structure. This segmentation allows the light extraction function to be concentrated in the inclined side surfaces of the n-type layer, enabling high light extraction efficiency in a compact footprint. The segmented design permits multiple such structures to be closely packed, achieving high resolution while maintaining effective light extraction area.
Solution Approach 2:
By creating inclined side surfaces through the trapezoidal n-type semiconductor layer, the patent utilizes lateral dimensions for light extraction rather than relying solely on vertical thickness. This dimensional approach increases the effective light extraction surface area without increasing the device footprint, thereby maintaining high resolution while improving light extraction efficiency.
3Ease of manufacture
If the semiconductor device uses a conventional planar structure, then the manufacturing process is straightforward, but the manufacturing yield is low
Solution Approach 1:
The patent incorporates a protection layer that covers the inclined side surfaces of the n-type semiconductor layer before subsequent manufacturing steps. This preliminary protection prevents damage to the critical inclined surfaces during handling, assembly, and further processing, thereby reducing defect rates and improving manufacturing yield without adding significant process complexity.
Solution Approach 2:
The trapezoidal structure with inclined side surfaces provides mechanical stability and facilitates alignment during assembly. The geometry naturally guides positioning and reduces sensitivity to alignment errors, improving manufacturing yield while maintaining process simplicity through standard fabrication techniques.
4Manufacturing precision
If the semiconductor device uses a compact design, then the display resolution is high, but the light extraction efficiency is reduced
Solution Approach 1:
The patent resolves this contradiction by utilizing the lateral dimensions through inclined side surfaces of the trapezoidal n-type semiconductor layer. This creates additional light extraction pathways without increasing the device footprint, enabling high light extraction efficiency in a compact design suitable for high-resolution displays.
Solution Approach 2:
The asymmetric trapezoidal geometry concentrates light extraction functionality in the inclined side surfaces, maximizing light extraction efficiency within a minimal footprint. This asymmetric design allows the device to maintain compact dimensions for high resolution while achieving effective light extraction through the strategically oriented inclined surfaces.
Data Source
AI summary
The semiconductor element according to an embodiment comprises: a light-emitting structure comprising a p-type semiconductor layer, an active layer disposed under the p-type semiconductor layer, and an n-type semiconductor layer disposed under the active layer; a protective layer disposed on the side surface and upper surface of the light-emitting structure; a p-type contact layer disposed over the p-type semiconductor layer; and an n-type contact layer disposed under the n-type semiconductor layer, wherein: the width of the lower surface of the n-type semiconductor layer is provided greater than that of the lower surface of the p-type semiconductor layer; the width of the upper surface of the n-type contact layer is provided greater than that of the upper surface of the n-type semiconductor layer; and the angle between the lower surface of the n-type semiconductor layer and the side surface of the light-emitting structure may be 30-80 degrees.