VCSEL Electrode Layout for Lower Obstruction and Contact Resistance
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Solution Overview
Problem
Existing semiconductor devices face challenges in efficiently emitting radiation due to obstruction by conductive layers, leading to reduced radiation output and increased contact resistance, which affects the coherence and efficiency of the emitted light.
Innovation Solution
The semiconductor device incorporates a bonding structure with columnar structures and insulating layers, featuring openings and electrodes positioned to minimize obstruction, allowing for efficient current flow and radiation emission, with specific electrode configurations to enhance coherence and reduce contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive layers are used to connect electrodes to semiconductor layers, then electrical connection is achieved, but radiation emission is obstructed and contact resistance increases
Solution Approach 1:
The patent extracts the harmful conductive layer material from the radiation emission region by forming openings in the insulating layer that expose the semiconductor contact layers directly to the electrode, eliminating the need for conductive layers in the radiation path while maintaining electrical connection
Solution Approach 2:
The patent introduces an insulating layer as an intermediary structure that allows the electrode to make direct contact with the semiconductor contact layer through openings, thereby eliminating the need for separate conductive layers while maintaining electrical connection and reducing radiation obstruction
2Reliability
If conductive layers are positioned over semiconductor contact layers, then electrical connection is established, but forward voltage increases and lasing efficiency decreases
Solution Approach 1:
The patent removes the conductive layer from the interface between the electrode and semiconductor contact layer, eliminating the additional contact resistance and forward voltage drop that would be introduced by the conductive layer, thereby improving lasing efficiency
Solution Approach 2:
The patent changes the dimensional arrangement by forming vertical openings through the insulating layer to the semiconductor contact layer, allowing direct electrical connection without the need for lateral conductive layer placement, thus reducing forward voltage
3Ease of manufacture
If symmetric electrode configuration is used, then manufacturing is simplified, but radiation coherence is reduced due to obstruction
Solution Approach 1:
The patent employs asymmetric electrode configuration where the first electrode has a larger area than the second electrode, and the openings in the insulating layer are positioned asymmetrically relative to the columnar structures, optimizing radiation coherence by minimizing obstruction in the primary emission direction while maintaining manufacturability
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
The solution enables improved radiation emission coherence and efficiency by minimizing conductive layer obstruction, enhancing current density in key emission regions, and optimizing the forward voltage, lasing threshold, and saturation current characteristics.
Implementation Method 1
An electrical current is injected into the active region through the first electrode and the second electrode to generate the light in the active region
Implementation Method 2
The VCSEL includes a structure having a pair of mirror stacks, and an active region formed between the pair of mirror stacks
Data Source
AI summary
A semiconductor device includes a bonding structure having a top, a back opposite the top, a first side and a second side opposite the first side, wherein the first side and the second side between the top and the back; and columnar structures over the back of the bonding structure. The columnar structures include a first columnar structure nearest to the first side and a second columnar structure nearest to the second side. The semiconductor device further includes a first electrode disposed over at least portion of the columnar structures and electrically connected to at least one of the columnar structures, and a second electrode disposed over at least portion of the back of the bonding structure and electrically connected to at least one of the columnar structures.