Micro VCSEL Mesa Structure for Transfer Alignment and Beam Quality
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Solution Overview
Problem
Conventional micro VCSEL arrays face efficiency degradation due to shifts during chip transfer, especially when chip and array sizes are reduced to several tens of μm, leading to adverse effects on operation.
Innovation Solution
A micro VCSEL chip design featuring a first and second reflector with distributed Bragg reflector pairs, a multiple quantum well layer, contact layers, and a passivation layer, with a mesa structure on one side and optimized metal layer areas to minimize errors and maintain beam quality during transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If VCSEL chip size is reduced to several tens of μm for high-density integration, then integration density is improved, but manufacturing precision and alignment accuracy deteriorate due to transfer errors
Solution Approach 1:
The patent applies preliminary action by forming the mesa structure on the contact layer before the chip transfer process. This pre-formed structure serves as a precise alignment reference that remains intact during transfer, enabling accurate positioning of the miniaturized VCSEL chip onto the array substrate without compromising alignment accuracy despite the reduced chip size
Solution Approach 2:
The patent introduces an intermediary alignment mark structure formed on the contact layer that mediates between the chip transfer process and the final alignment requirement. This intermediary structure provides a robust reference that is less sensitive to transfer errors, allowing high-density integration to be achieved while maintaining manufacturing precision
2Quantity of substance
If VCSEL chip size is reduced to several tens of μm for high-density integration, then integration density is improved, but operational reliability deteriorates due to sensitivity to transfer errors
Solution Approach 1:
The mesa structure is preliminarily formed on the contact layer before transfer, creating a robust mechanical and electrical connection framework that is less susceptible to damage from transfer-induced stress. This preliminary structuring enhances the reliability of miniaturized chips during the transfer process
Solution Approach 2:
The patent applies beforehand cushioning by designing the mesa structure with appropriate dimensions and material composition that can absorb and distribute mechanical stress during transfer. This cushioning effect protects the sensitive active regions of the miniaturized VCSEL chip, maintaining operational reliability despite the reduced size and increased sensitivity
3Device complexity
If contact layer has mesa structure on one side only, then manufacturing complexity is reduced, but beam quality may be affected
Solution Approach 1:
The patent applies local quality by forming the mesa structure on only one side of the contact layer rather than symmetrically on both sides. This asymmetric local modification simplifies the manufacturing process while the mesa structure's specific geometry and positioning are optimized to maintain the necessary optical properties and beam quality for VCSEL operation
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 manufacturing efficiency and minimizes efficiency degradation by ensuring accurate alignment and contact during transfer, maintaining improved beam quality and operational stability.
Implementation Method 1
a first reflector including a plurality of distributed Bragg reflector (DBR) pairs, a second reflector including a plurality of DBR pairs
Implementation Method 2
a multiple quantum well layer positioned between the first reflector and the second reflector and recombining holes generated from one of the first reflector and the second reflector and electrons generated from the other of the first reflector and the second reflector
Data Source
AI summary
Disclosed are a micro VCSEL with improved beam quality and a micro VCSEL array. An embodiment of the present invention provides a micro VCSEL with improved beam quality of light or laser to be oscillated and a micro VCSEL array capable of improving manufacturing efficiency and minimizing efficiency degradation due to errors occurring during a transfer.