Semiconductor device
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Solution Overview
Problem
Semiconductor devices, particularly ultraviolet light emitting devices, face challenges with low light extraction efficiency and high operating voltage due to poor electric current spreading characteristics and inefficient optical output power.
Innovation Solution
The semiconductor device incorporates a configuration with recesses and specific electrode structures, including a second electrode pad with a convex portion to enhance light extraction efficiency, and a reflective layer to improve electric current spreading and optical output power, while adjusting the aluminum composition and insulation layers to optimize electrical and optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional ultraviolet light emitting device structure is used, then the device can be manufactured with standard processes, but the light extraction efficiency is low
Solution Approach 1:
The patent introduces a convex portion on the second electrode pad that extends in the thickness direction of the semiconductor device. This dimensional change creates a protruding structure that redirects light extraction paths, allowing light to escape more efficiently from regions that would otherwise be trapped in the planar structure. The convex portion effectively adds a vertical dimension to the electrode design to solve the light extraction problem.
Solution Approach 2:
The convex portion of the second electrode pad acts as an intermediary structure between the light emitting region and the external environment. It serves as a mediator that captures light generated in the active layer and redirects it toward the light extraction surface, improving the overall light extraction efficiency without requiring complex external optical components.
2Ease of manufacture
If the device structure is simplified for easy manufacturing, then production cost is reduced, but electric current spreading efficiency deteriorates
Solution Approach 1:
The second electrode pad is segmented into a convex portion and a flat portion, with each serving distinct functions. The convex portion is positioned to optimize light extraction while the flat portion provides a stable bonding surface. This segmentation allows the electrode to simultaneously achieve good current spreading and efficient light extraction without complicating the manufacturing process.
Solution Approach 2:
Different regions of the second electrode pad are given different geometries to perform different functions. The convex portion locally concentrates electromagnetic field to enhance light extraction, while the flat portion maintains good electrical contact and current spreading. This local differentiation of quality allows the single electrode structure to fulfill multiple requirements.
3Use of energy by moving object
If the operating voltage is reduced to lower power consumption, then energy efficiency improves, but optical output power decreases
Solution Approach 1:
The patent optimizes the aluminum composition gradient in the AlGaN layers and adjusts the geometric parameters of the convex portion (height, width, position) to simultaneously improve electrical and optical characteristics. By carefully controlling these parameters, the device achieves low operating voltage while maintaining high optical output power through enhanced light extraction efficiency.
4Loss of energy
If recesses are added to improve light extraction, then light extraction efficiency increases, but device complexity increases
Solution Approach 1:
Instead of adding recesses that require complex etching processes from the top surface, the patent introduces a convex portion that extends upward from the second electrode pad. This vertical protrusion can be formed using standard semiconductor fabrication techniques and provides effective light extraction enhancement without significantly increasing device complexity or requiring additional processing steps.
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 significantly enhances light extraction efficiency, reduces operating voltage, and increases optical output power by improving electric current spreading and light reflection within the semiconductor device.
Implementation Method 1
a reflective layer to improve electric current spreading and optical output power
Data Source
Figure 1
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AI summary
An embodiment includes a semiconductor device including a semiconductor structure including a first conductive semiconductor layer, a second conductive semiconductor layer, and an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer; a first insulation layer disposed on the semiconductor structure; a first electrode disposed on the first conductive semiconductor layer; a second electrode disposed on the second conductive semiconductor layer; a first cover electrode disposed on the first electrode; a second cover electrode disposed on the second electrode; and a second insulation layer extending from an upper surface of the first cover electrode to an upper surface of the second cover electrode. The semiconductor structure includes a first surface extending from an upper surface of the first conductive semiconductor layer where the first electrode is disposed to a side surface of the active layer and an upper surface of the second conductive semiconductor where the second electrode is disposed. The first insulation layer is disposed on the first surface to be spaced apart from the first electrode. The first insulation layer is disposed on the first surface to overlap with the first cover electrode in a first direction perpendicular to the upper surface of the first conductive semiconductor layer.