GaN Light Emitting Device Trench Electrode Current Diffusion
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Solution Overview
Problem
Conventional light emitting devices using GaN materials face issues with non-uniform current diffusion due to low conductivity of the P-type GaN layer, leading to uneven light emission, as the double-layered Ni and Au structure reduces transparency and quantum efficiency.
Innovation Solution
The formation of trenches with a mesh structure in the P-type semiconductor layer and active layer to expose the N-type semiconductor layer, filled with a conductive layer, along with a transparent electrode and insulating layers, ensures uniform current diffusion and improved light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-layered Ni and Au conductive layer is formed on the P-type GaN layer to improve current diffusion, then current diffusion capability is improved, but transparency is lowered and photons are absorbed, reducing quantum efficiency
Solution Approach 1:
The patent divides the conductive layer into multiple segments: a lower conductive layer (Ni/Au double-layer) formed in trenches to provide current diffusion, and an upper transparent conductive layer (such as ITO or ZnO) formed on the P-type GaN layer to provide transparency. This segmentation allows each layer to perform its specialized function without compromising the other.
Solution Approach 2:
The patent transitions from a single-planar conductive layer to a multi-layered vertical structure. The lower conductive layer is positioned in trenches (depth dimension) while the upper transparent layer covers the surface (surface dimension), creating a three-dimensional architecture that simultaneously achieves current diffusion and optical transparency.
2Reliability
If an extension electrode is formed to improve current diffusion characteristic, then current diffusion is improved, but light emission remains non-uniform with dark regions between electrodes
Solution Approach 1:
The patent segments the electrode structure into multiple components: extension electrodes that extend from the P-type electrode along the outline to improve current diffusion, and mesh-shaped trenches that divide the active layer into multiple regions. This segmentation allows current to be distributed through multiple pathways, preventing dark regions and achieving uniform light emission.
Solution Approach 2:
The patent creates a dynamic current distribution network through the mesh structure, where current can flow through multiple parallel pathways via the conductive layer filled trenches. This dynamic routing of current ensures uniform distribution across the entire active layer, eliminating stagnant regions that cause non-uniform light emission.
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 enables uniform light emission by ensuring consistent current distribution across the device, enhancing light emitting efficiency and external quantum efficiency.
Implementation Method 1
a conductive layer filled in the trenches having the first insulating layer formed therein
Implementation Method 2
trenches of a mesh structure are formed by etching a P-type semiconductor layer and an active layer to expose an N-type semiconductor layer
Implementation Method 3
electrons provided from the N-type GaN layer and holes provided from the P-type GaN layer are recombined in the active layer, thereby emitting short-wavelength light corresponding to green or blue
Data Source
AI summary
There are provided a light emitting device and a method of manufacturing the same. A light emitting device according to the present invention includes a substrate; an N-type semiconductor layer, an active layer and a P-type semiconductor layer, sequentially formed on the substrate; one or more trenches formed to expose the N-type semiconductor layer by partially removing at least the P-type semiconductor and active layers; a first insulating layer formed on sidewalls of the trenches; and a conductive layer filled in the trenches having the first insulating layer formed therein. According to the present invention, it is possible to obtain a characteristic of uniform current diffusion, and thus, light is uniformly emitted to thereby enhance the light emitting efficiency.