Photodiode Array Laser Fusion Cross Talk
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Solution Overview
Problem
Conventional photodiode arrays face challenges with cross talk between pixels, which are typically addressed by forming trench grooves and filling them with insulating material, a process that is time-consuming and reduces mechanical strength if the filling step is omitted.
Innovation Solution
The formation of crystal fused regions between photodiodes, achieved by epitaxially growing semiconductor layers and using laser irradiation to fuse the semiconductor material, preventing carrier leakage and thus cross talk without the need for trench grooves or insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trench grooves are formed and filled with insulating material to prevent cross talk, then cross talk prevention is improved, but manufacturing complexity and time increase
Solution Approach 1:
The invention extracts and eliminates the trench groove formation and insulating material filling steps from the manufacturing process. Instead of using physical trenches filled with insulators, the patent uses laser irradiation to directly modify the semiconductor material between pixels, creating electrical isolation without the complex multi-step trench formation process
Solution Approach 2:
The invention replaces the mechanical approach of forming physical trenches and filling them with insulating materials with a laser-based optical process. The laser irradiation directly modifies the semiconductor material's electrical properties through optical energy, substituting mechanical fabrication steps with an optical field-based process
2Reliability
If trench grooves are formed to prevent cross talk, then cross talk prevention is improved, but mechanical strength decreases
Solution Approach 1:
The invention removes the physical trench groove structure entirely from the device architecture. By using laser irradiation to create electrical isolation zones within the continuous semiconductor substrate, the method eliminates the need for physical grooves that would compromise mechanical strength
Solution Approach 2:
The invention changes the electrical parameters of the semiconductor material through laser irradiation rather than physically removing material. The laser modifies the crystal structure or creates defect zones that prevent carrier leakage, achieving electrical isolation while preserving the continuous physical structure and mechanical integrity of the substrate
3Reliability
If multiple steps (trench formation, insulating layer formation, filling) are used to prevent cross talk, then cross talk prevention is improved, but productivity decreases
Solution Approach 1:
The invention merges multiple separate manufacturing steps (trench formation, insulating layer deposition, and filling) into a single laser irradiation process. The laser treatment simultaneously achieves electrical isolation and defines the pixel boundaries in one operation, eliminating the need for sequential processing steps
Solution Approach 2:
The laser irradiation process can be performed continuously across the semiconductor substrate without interruption for intermediate steps like insulating layer deposition. The laser beam can scan across multiple pixels in sequence, maintaining continuous processing action and eliminating idle time between manufacturing steps
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 manufacturing process, maintains mechanical strength, and effectively prevents cross talk between photodiodes, enhancing the photodiode array's performance and resolution by eliminating the need for physical grooves and reducing processing complexity.
Implementation Method 1
multiphoton absorption is generated because the laser light is irradiated and converged, and thereby the crystal can be fused
Implementation Method 2
forming crystal fused regions by adjusting converging points to the insides of the first semiconductor layer and semiconductor substrate and by being irradiated by laser lights along spaces between the plurality of second semiconductor layers to fuse the first semiconductor layer and the semiconductor substrate
Data Source
AI summary
Disclosed is a photodiode array comprising a semiconductor substrate; a plurality of photodiodes formed on the semiconductor substrate; and crystal fused regions losing crystallinity by fusing a semiconductor material of the photodiodes between the plurality of photodiodes.