Semiconductor Bonding Structure With Low-Loss Intermediate Layer
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Solution Overview
Problem
The complex and costly surface preparation steps required for direct bonding between thin working layers and carrier substrates in VCSEL production can disrupt the quality of III-V semiconductor layers, leading to potential disruptions in the operation of vertical-cavity surface-emitting lasers (VCSELs).
Innovation Solution
A semiconductor structure is developed with a first crystalline semiconductor layer joined to a second crystalline semiconductor layer via an intermediate layer with a refractive index close to both layers, having a low attenuation coefficient, which simplifies the bonding process and reduces light signal disruption, using materials like amorphous silicon as the intermediate layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If direct bonding is used between thin working layer and carrier substrate, then bonding strength is improved, but surface preparation complexity increases
Solution Approach 1:
An intermediate layer is introduced between the thin working layer and the carrier substrate to facilitate bonding. This intermediate layer acts as a mediator that enables bonding without requiring complex surface preparation steps on the III-V semiconductor layers, thus maintaining bonding strength while reducing process complexity
Solution Approach 2:
The bonding interface is segmented into multiple components: the thin working layer, the intermediate layer, and the carrier substrate. This segmentation allows each component to be optimized independently, with the intermediate layer specifically designed to simplify the bonding process while the other layers maintain their functional requirements
2Reliability
If chemical surface preparation steps are performed, then bonding quality is improved, but cost increases
Solution Approach 1:
The intermediate layer serves as a mediator that reduces the need for expensive chemical surface preparation steps. By providing a bonding interface that is more tolerant to surface conditions, it maintains bonding quality while reducing manufacturing costs associated with complex chemical treatments
3Ease of manufacture
If intermediate layer with different refractive index is used, then bonding is facilitated, but light signal attenuation increases
Solution Approach 1:
The refractive index of the intermediate layer is carefully selected and optimized to balance two competing requirements: it differs enough from the III-V layers to facilitate bonding while being close enough to minimize light signal attenuation. This parameter optimization allows the intermediate layer to serve both bonding and optical transmission functions
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 simplifies the fabrication of VCSELs by reducing the complexity and cost of surface preparation, ensuring high-quality bonding and minimizing light signal attenuation, thereby enhancing the efficiency and performance of optoelectronic components.
Implementation Method 1
an intermediate layer having a refractive index very close to those of the first and second layers... the intermediate layer further has a very low attenuation coefficient
Implementation Method 2
intermediate layer having a refractive index very close to those of the first and second layers
Data Source
AI summary
A semiconductor structure for optoelectronic applications; comprises a first layer made of a crystalline semiconductor, the layer being disposed on an intermediate layer including or adjacent to a direct-bonding interface, the intermediate layer being disposed on a second layer made of a crystalline semiconductor material. The intermediate layer is composed of a material that is different from those of the first and second layers, and the attenuation coefficient of which is lower than 100. The refractive index of the intermediate layer differs by less than 0.3 from the refractive index of at least one sub-layer of the first layer adjacent to the intermediate layer, and of at least one sub-layer of the second layer adjacent to the intermediate layer.