Light-Emitting Device With Angled Sidewalls
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Solution Overview
Problem
Conventional light-emitting devices face challenges in increasing the light-emitting area and improving the adhesion capability of the conductive layer, leading to reduced light-emitting intensity and performance due to excessive semiconductor material removal during etching and poor bridge circuit adhesion.
Innovation Solution
The solution involves a light-emitting device design with a substrate and a first light-emitting unit comprising semiconductor layers and a light-emitting layer, where the semiconductor layers have angled sidewalls with different slopes to minimize semiconductor material removal and enhance adhesion, and a method involving patterned photoresist layers and a sacrifice layer to control etching and form a conductive layer with improved adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photolithography and etching processes are used to form bridge circuits, then the adhesion capability of metal during evaporation is improved, but excessive semiconductor material is removed causing light-emitting area shrinkage
Solution Approach 1:
The patent applies preliminary action by forming a slope structure on the semiconductor substrate before depositing the metal bridge circuit. This pre-formed slope structure provides a favorable surface geometry that enhances metal adhesion during evaporation while preserving the light-emitting area, as the slope is created through controlled etching that removes minimal material compared to conventional vertical wall structures.
Solution Approach 2:
The patent changes the geometric parameters of the semiconductor structure by creating a slope with specific angle and dimensions. The slope structure parameters (angle, height, width) are optimized to balance adhesion enhancement with light-emitting area preservation, representing a parameter change approach to resolve the contradiction between reliability and area.
2Ease of manufacture
If conventional etching processes are used with photoresist masks, then bridge circuit formation is achieved, but production cost increases due to excessive material removal
Solution Approach 1:
The slope structure is formed as a preliminary step before bridge circuit fabrication, enabling subsequent metal deposition to proceed with better adhesion. This preliminary geometric preparation reduces the need for aggressive etching and material removal, thereby lowering production costs while maintaining ease of manufacture for the bridge circuit.
Solution Approach 2:
The patent employs a disposable sacrificial layer (such as oxide or nitride layer) that is intentionally removed after serving its purpose of defining the bridge circuit pattern. This sacrificial approach allows for precise pattern formation without excessive semiconductor material loss, making the manufacturing process more cost-effective.
3Device complexity
If metal bridge circuits are deposited on flat surfaces, then the manufacturing process is simple, but adhesion capability is poor causing voids and defects
Solution Approach 1:
The patent introduces curvature by forming a slope structure with inclined surfaces instead of flat or vertical walls. This curved/sloped geometry enhances metal adhesion during evaporation by providing increased surface area and favorable stress distribution, improving reliability without significantly complicating the manufacturing process.
Solution Approach 2:
The slope structure is prepared in advance before metal deposition, creating an optimized surface geometry that inherently improves adhesion. This preliminary geometric modification eliminates the need for complex post-deposition adhesion treatments or multi-layer metal stacks, maintaining manufacturing simplicity while enhancing reliability.
Data Source
AI summary
A light-emitting device includes a substrate and a first light-emitting unit. The first light-emitting unit is disposed on the substrate, and includes a first semiconductor layer, a first light-emitting layer, and a second semiconductor layer. The first semiconductor layer is disposed on the substrate. The first light-emitting layer is disposed between the first semiconductor layer and the second semiconductor layer. The second semiconductor layer is disposed on the first light-emitting layer. The first semiconductor layer has a first sidewall and a second sidewall. A first angle is between the substrate and the first sidewall. A second angle is between the substrate and the second sidewall. The first angle is smaller than the second angle.