InP Regrowth Structure With AlGaInAs Bonding for Thermal Strain Relief
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The integration of III-V semiconductors on silicon waveguide circuits faces challenges due to thermal strain effects and limited thickness of regrown III-V material, leading to reduced material quality and surface roughness, which restricts the design of photonic devices like lasers.
Innovation Solution
A device with a Si substrate, a SiO2 interface layer, and a bonding layer made of AlGaInAs alloy, lattice-matched with InP, allows for thick regrowth of III-V material by mitigating thermal strain, enabling increased thickness and improved material quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If regrowth of thick III-V structures is performed on directly bonded InP-SiO2/Si membrane, then the lattice mismatch and polarity differences are avoided, but thermal strain induces surface roughness increase and material quality degradation
Solution Approach 1:
A sacrificial InP layer is introduced as an intermediary between the SiO2/Si substrate and the regrown III-V structure. This intermediary layer absorbs the thermal strain during epitaxial regrowth, preventing direct transmission of stress to the final device structure. The sacrificial layer is later removed to leave a high-quality thick III-V structure with low surface roughness and maintained material quality.
2Adaptability or versatility
If regrowth thickness is increased to enable complex photonic device designs, then device functionality is improved, but surface roughness RMS increases and material quality decreases
Solution Approach 1:
The sacrificial InP layer serves as a cushioning element that pre-absorbs thermal strain before the actual device regrowth occurs. This beforehand cushioning allows thick structures (up to 3 μm and beyond) to be regrown without the cumulative surface roughness penalty that would normally occur, enabling complex photonic device designs while maintaining manufacturing precision.
3Manufacturing precision
If total regrown thickness is limited to half micron to maintain material quality, then surface roughness is controlled, but laser design options are restricted
Solution Approach 1:
The sacrificial InP layer acts as a mediator that decouples the thickness constraint from the material quality constraint. By placing this intermediary between the substrate and the regrown structure, the system can accommodate thick regrown layers (exceeding 0.5 μm) while the intermediary absorbs the strain, thereby maintaining material quality and enabling diverse laser designs including vertical p-i-n junctions.
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 enables the regrowth of thick III-V structures with reduced surface roughness and enhanced material quality, allowing for more complex photonic device designs, such as 3 μm-thick vertical p-i-n junctions, while maintaining high bonding strength and stability.
Implementation Method 1
a bonding layer on the interface layer, said bonding layer being made of a III-V material consisting of an alloy of the AlGaInAs material family
Implementation Method 2
At a typical epitaxial growth temperature (610° C.-650° C.), this difference induces a thermal strain in the growing layer
Implementation Method 3
Several and separate epitaxial steps can follow each other, such as selective area growth, butt-joint regrowth, cladding regrowth, lateral regrowth
Data Source
AI summary
A device for regrowth of a thick structure lattice-matched with InP comprising: a Si substrate, an interface layer of SiO2 on the Si substrate, a bonding layer on the interface layer, said bonding layer being made of a III-V material consisting of an alloy of the AlGaInAs family, and a regrowth layer on the bonding layer, said regrowth layer being made of InP.