LED Insulating Layer Prevents Short-Circuits
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Solution Overview
Problem
Light emitting diodes (LEDs) face challenges with electrical insulation, particularly due to the thin thickness of the second conduction type semiconductor layer, which can lead to short-circuits with external foreign substances, compromising the device's reliability and efficiency.
Innovation Solution
The implementation of an insulating layer, specifically a nitride layer like AlxGa1-xN, is introduced between the second electrode layer and the second conduction type semiconductor layer, along with a passivation layer on lateral surfaces, to enhance electrical insulation and prevent short-circuits by spacing the semiconductor layers further apart.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the second conduction type semiconductor layer is made thin to reduce device complexity, then the manufacturing process is simplified, but electrical insulation deteriorates leading to short-circuits with external foreign substances
Solution Approach 1:
An insulating layer is introduced as an intermediary between the second metal layer and the second conduction type semiconductor layer. This insulating layer acts as a mediator that prevents direct contact and potential short-circuits, while still allowing the device to maintain its compact structure with the thin semiconductor layer.
Solution Approach 2:
The solution moves from a single-plane contact arrangement to a multi-dimensional structure by adding the insulating layer in the vertical dimension. This creates a three-dimensional arrangement where the insulating layer is disposed on the peripheral portion of the upper surface of the second metal layer and extends upward, providing insulation without increasing the horizontal footprint of the device.
2Use of energy by moving object
If the second conduction type semiconductor layer is made thin to improve light emission efficiency, then light extraction is enhanced, but electrical insulation deteriorates causing short-circuits
Solution Approach 1:
The insulating layer serves as a mediator that enables the semiconductor layer to be made thin for improved light emission while simultaneously preventing electrical short-circuits. The insulating layer is positioned to provide electrical isolation without interfering with the light emission function of the thin semiconductor layer.
3Area of stationary object
If the semiconductor layers are placed close together to reduce device size, then the device footprint is minimized, but electrical insulation deteriorates leading to short-circuits with foreign substances
Solution Approach 1:
The insulating layer utilizes the vertical dimension to provide electrical insulation without increasing the horizontal footprint of the device. By extending the insulating layer upward from the peripheral portion of the metal layer, the solution achieves electrical isolation while maintaining a compact device footprint.
Solution Approach 2:
The insulating layer acts as an intermediary that enables close spacing of semiconductor layers in the horizontal plane while providing the necessary electrical insulation through its vertical extension, thus resolving the contradiction between compact footprint and electrical isolation.
Data Source
AI summary
A light emitting device includes a second metal layer, a second semiconductor layer on the second metal layer, an active layer on the second semiconductor layer, a first semiconductor layer on the active layer, a first metal layer on the first semiconductor layer, an insulating layer between the second metal layer and the second semiconductor layer at a peripheral portion of an upper surface of the second metal layer, and a passivation layer surrounding lateral surfaces of the insulating layer, the second semiconductor layer, the active layer, and the first semiconductor layer, the passivation layer being on the second metal layer, wherein a lateral surface of the insulating layer is adjacent to a lateral surface of the second metal layer, and wherein a lowermost surface of the passivation layer is disposed lower than a lowermost surface of the insulating layer.