VCSEL Array Edge Isolation Trench for Leakage Control
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Solution Overview
Problem
Current VCSEL designs using ion implantation and dicing streets introduce performance drifts, reverse leakage current, and long-term reliability issues, increasing fabrication complexity and costs.
Innovation Solution
A VCSEL chip design that eliminates ion implantation and dicing streets by incorporating an isolation trench at the chip's edge to block current spreading and prevent defects, using oxidation trenches for current confinement and optical index guiding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ion implantation and dicing streets are used in VCSEL designs, then current confinement is achieved, but performance drifts, reverse leakage current, and long-term reliability issues occur
Solution Approach 1:
The patent removes the harmful ion implantation process and dicing streets from the VCSEL structure, extracting the source of reliability issues while maintaining current confinement through alternative means (oxide apertures and isolation trenches)
Solution Approach 2:
The patent introduces oxide apertures and isolation trenches as intermediary structures that provide current confinement without the harmful effects of ion implantation, acting as mediators between the need for current control and the desire for reliability
2Ease of manufacture
If ion implantation is used for current confinement, then current spreading is blocked, but fabrication complexity and costs increase
Solution Approach 1:
The patent replaces the mechanical/ion-based implantation process with a chemical/oxidation-based approach using oxide apertures and isolation trenches, substituting a complex ion implantation system with simpler oxidation processes
3Device complexity
If dicing streets are used to separate emitters, then emitter isolation is achieved, but defect propagation is prevented only at the cost of increased fabrication complexity
Solution Approach 1:
The isolation trenches serve multiple functions simultaneously: they provide emitter isolation, block defect propagation, and maintain structural integrity, replacing the need for separate dicing streets while reducing overall device complexity
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 design enhances reliability and reduces fabrication complexity and costs while maintaining performance by preventing current leakage and defect propagation, without additional process steps.
Implementation Method 1
one or more oxide layers, wherein an oxide aperture is formed through the one or more oxide layers for current confinement and optical index guiding
Data Source
AI summary
A vertical-cavity surface-emitting laser (VCSEL) emitter device includes a highly-doped cap layer; and a stacked structure comprising a top surface and an edge region. The highly-doped cap layer is arranged on the top surface. The stacked structure includes a bottom distributed Bragg reflector (DBR) mirror; a top DBR mirror; an active area arranged between the top DBR mirror and the bottom DBR mirror and configured to generate laser light; and at least one oxide layer, wherein an oxide aperture is formed through the at least one oxide layer for current confinement and optical index guiding. An isolation trench is arranged at the edge region, wherein the isolation trench extends through the highly-doped cap layer and into the stacked structure, including partially into the bottom DBR mirror, and wherein the isolation trench is configured to block current from spreading into the edge region via the highly-doped cap layer.