Surface Emitting Laser Array With Dummy Mesa Wiring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing surface emitting laser array elements face challenges in achieving reliable and cost-effective manufacturing due to variations in etching rates, fragile AlAs layers, and wiring disconnection issues, particularly when forming densely integrated two-dimensional arrays, which affect laser characteristics and production yield.
Innovation Solution
A surface emitting laser array element is designed with a lower DBR, active layer, and upper DBR, featuring quadrangular prism-shaped mesas and dummy mesas to stabilize etching rates and wiring connections, using ICP dry etching and selective oxidation to form current-confined regions, and arranging wiring over dummy mesas to reduce electrical resistance and prevent disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AlAs is used as the current-confined layer material, then production yield and throughput are improved, but the layer becomes fragile and prone to breakage during manufacturing
Solution Approach 1:
The patent introduces a buffer layer between the AlAs current-confined layer and the underlying structures. This buffer layer acts as a cushioning element that prevents direct stress concentration on the fragile AlAs layer during manufacturing processes, thereby reducing breakage while maintaining the high productivity benefits of using AlAs material.
Solution Approach 2:
The patent employs a buffer layer as an intermediary structure between the fragile AlAs current-confined layer and the substrate or lower layers. This intermediary element mediates the mechanical stresses, protecting the AlAs layer from breakage during handling and processing while allowing the manufacturing process to proceed efficiently.
2Ease of manufacture
If contact exposure is used for forming resist patterns, then manufacturing cost is reduced, but the AlAs layer breaks due to pressure from the exposure device
Solution Approach 1:
The buffer layer is positioned beneath the AlAs current-confined layer to provide beforehand cushioning during the contact exposure process. When the exposure device applies pressure to the resist pattern, the buffer layer absorbs and distributes this pressure, preventing direct transmission of stress to the fragile AlAs layer and avoiding breakage while allowing cost-effective contact exposure to be used.
3Area of stationary object
If wiring is formed between mesas, then space utilization is improved, but wiring disconnection occurs due to step coverage limitations
Solution Approach 1:
The patent transitions the wiring path from a purely planar route between mesas to a three-dimensional path that traverses over the top surface of dummy mesas. This dimensional change allows wiring to bypass the step coverage problem at mesa edges while still achieving compact space utilization through the vertical relief provided by the dummy mesa structures.
Solution Approach 2:
The dummy mesas serve as intermediary structures that provide a smooth, continuous surface for wiring deposition. By placing wiring over these intermediary dummy mesas rather than directly between the functional mesas, the patent eliminates the step coverage issue that causes wiring disconnection while maintaining efficient space utilization.
4Manufacturing precision
If dummy mesas are added to stabilize etching rates, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The dummy mesas are designed to serve multiple functions: they stabilize the etching rate by providing uniform stress distribution during the etching process, and they simultaneously serve as support structures for wiring deposition. This multi-functionality reduces the overall device complexity by combining what could be separate elements into a single integrated feature.
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 results in a reliable and cost-effective surface emitting laser array element with improved laser characteristics and production yield, enabling the formation of high-resolution, high-quality images in image forming apparatuses.
Implementation Method 1
performing ICP dry etching on the upper DBR
Implementation Method 2
performing ICP dry etching on the upper DBR
Implementation Method 3
steam oxidation is performed to oxidize a part of the current-confined layer from its side face to form a selectively oxidized region made of AlxOy
Implementation Method 4
lower distributed bragg reflector (DBR) that is formed on a substrate, an active layer that is formed on the lower DBR, and an upper DBR that is formed on the active layer
Data Source
AI summary
A surface emitting laser array element is disclosed that includes a lower distributed bragg reflector (DBR) that is formed on a substrate, an active layer that is formed on the lower DBR, and an upper DBR that is formed on the active layer. A mesa and a dummy mesa that is arranged at a periphery of the mesa are created by removing a portion of the upper DBR. The mesa forms a surface emitting laser, and a wiring is connected to an electrode that is formed on an upper face of the mesa. The wiring includes a portion that is arranged over an upper face of the dummy mesa, a side face of the dummy mesa, and a bottom face at a peripheral region of the dummy mesa extending along a longitudinal direction of the wiring.