Nitride Semiconductor Light Emitting Device Electrode Structure
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Solution Overview
Problem
Nitride semiconductor light emitting devices with a planar structure face issues with non-uniform current spreading, leading to reduced effective light emission area and efficiency, especially in larger devices intended for illumination.
Innovation Solution
The introduction of insulation layers to isolate bonding pad regions and the use of extension electrodes that are disposed in parallel with each other, ensuring uniform current distribution across the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bonding pads are formed in large areas for wire bonding, then wire bonding is facilitated, but current becomes concentrated near the bonding pads, hindering uniform current spreading
Solution Approach 1:
The electrode structure is divided into two distinct parts: bonding pads for wire bonding and extension electrodes for current distribution. The extension electrodes are separated from the bonding pads by insulation layers, creating independent functional zones that prevent current concentration while maintaining wire bonding capability.
Solution Approach 2:
Insulation layers are introduced as intermediary elements between the bonding pads and the light emitting structure. These insulation layers prevent direct electrical contact, forcing current to flow through the extension electrodes instead of concentrating at the bonding pads, thus achieving uniform current distribution.
2Ease of manufacture
If a planar structure is used with two electrodes disposed horizontally, then manufacturing is simplified, but current cannot be uniformly spread in the entire light emission area, reducing effective area and light emission efficiency
Solution Approach 1:
The electrode configuration transitions from simple horizontal bonding pads to an extended three-dimensional structure with extension electrodes that reach across the light emitting area. The extension electrodes project outward from the bonding pads, creating a broader current distribution path that covers the entire light emission area while maintaining the planar substrate architecture.
Data Source
AI summary
The invention relates to a high-output nitride light emitting device. The light emitting device includes a first conductivity type nitride semiconductor layer, an active layer and a second conductivity type nitride semiconductor layer deposited in their order on a substrate. The light emitting device also includes first and second insulation layers formed in different upper surface portions of the nitride semiconductor light emitting device, and first and second bonding pads formed respectively on the first and second insulation layers. The light emitting device further includes first and second extension electrodes extended from the first and second bonding pads and coupled respectively to the first and second conductivity semiconductor layers. The electrode arrangement according to the present invention prevents direct coupling between the bonding pads and the light emitting device, thus allowing a symmetrical structure that can achieve more uniform current spreading using only the extension electrodes.