Semiconductor Optical Device Wiring Reduces Capacitive Coupling
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Solution Overview
Problem
Existing semiconductor optical devices face challenges in reducing capacitive coupling between wiring conductors and photodiode terminals, leading to increased dark current and fabrication complexities due to air-bridge wiring structures.
Innovation Solution
A semiconductor optical device design featuring a substrate with specific area configurations, semiconductor laminates, and a resin body that separates wiring conductors from the conductivity-type semiconductor layers, reducing capacitive coupling and dark current through a butt-joint junction and protective film coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air-bridge wiring structure is used to reduce capacitive coupling, then coupling capacitance between wiring conductors is reduced, but fabrication complexity increases and manufacturing difficulty increases
Solution Approach 1:
The harmful capacitive coupling effect is extracted and eliminated by removing the problematic air-bridge wiring structure. Instead, a planar wiring structure with increased spacing between conductors is used, which achieves the same goal of reducing coupling capacitance without the fabrication complexity of air-bridges.
Solution Approach 2:
Instead of using elevated air-bridge structures to reduce coupling, the invention inverts the approach by using a planar structure with increased horizontal spacing and lower dielectric constant materials, achieving reduced capacitance through geometric inversion rather than vertical elevation.
2Object-affected harmful factors
If air-bridge wiring structure is used to reduce capacitive coupling, then coupling capacitance between wiring conductors is reduced, but manufacturing precision requirements increase due to peeling-off risks and resist residuals
Solution Approach 1:
The invention replaces the fragile, precision-critical air-bridge structure with a robust planar wiring structure that is less susceptible to manufacturing variations. The planar structure tolerates normal fabrication variations without causing peeling-off or resist residual issues, effectively making the design more forgiving of manufacturing imperfections.
Solution Approach 2:
The design incorporates increased spacing and protective measures in advance to cushion against potential manufacturing defects. The planar structure's geometric margins provide a buffer that prevents the kinds of failures seen in air-bridge structures, where small deviations can cause peeling or residue problems.
3Ease of manufacture
If conventional wiring structure is used, then fabrication process is simpler, but capacitive coupling increases leading to increased dark current
Solution Approach 1:
The invention applies local quality optimization by selectively increasing spacing in critical areas where capacitive coupling affects dark current, while maintaining standard wiring practices in non-critical areas. This allows simple fabrication processes to be combined with localized capacitance reduction to suppress dark current.
Solution Approach 2:
The invention changes key parameters of the wiring structure - specifically increasing the spacing between conductors and using materials with lower dielectric constants - to reduce capacitive coupling. These parameter changes effectively reduce dark current while maintaining compatibility with standard fabrication processes.
Data Source
AI summary
A semiconductor optical device has a substrate including a primary surface with first to fourth areas; a first conductivity-type semiconductor layer disposed on the third and fourth areas; a first semiconductor laminate disposed on the first conductivity-type semiconductor layer and the third area; a resin body disposed on the second to fourth areas; a first electrode connected with the first semiconductor laminate through a first opening of the resin body in the third area; a first pad electrode disposed on the first area; and a wiring conductor extending on a first side and a top of the resin body in the second and third areas and on the first area to connect the first electrode to the first pad electrode. The first side of the resin body is disposed in the second area. The first semiconductor laminate includes a second conductivity-type semiconductor region being in contact with the first electrode.