Diode Array Trench Segmentation for Optical Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing photo-emitting and photo-receiving diode devices face challenges in increasing resolution without damaging lateral flanks and accommodating variable diode density, leading to decreased performance and optical interferences.
Innovation Solution
A diode array structure featuring a stack of semiconductor layers with trenches that surround diode regions, dielectric portions covering lateral flanks, and second trenches that do not pass through the interface between layers, reducing damage and allowing for variable diode density and improved optical insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If trenches pass through the entire thickness of the semiconductor stack to physically separate diodes, then manufacturing precision and diode separation are improved, but the lateral flanks of the diodes are damaged causing decreased external quantum efficiency
Solution Approach 1:
The patent divides the trench structure into two segments: first trenches that pass through the entire thickness for electrical separation, and second trenches that only partially penetrate the first layer for optical separation without damaging the interface. This segmentation allows each trench type to perform its specific function without causing harm to the diode structure.
Solution Approach 2:
The patent applies different trench penetration depths at different locations within the semiconductor stack. The first trenches extend through the full thickness where electrical isolation is needed, while the second trenches are limited to partial penetration in regions where optical isolation is sufficient without requiring full thickness etching, thus preserving the lateral flanks.
2Manufacturing precision
If the unit size of pixels is decreased to increase resolution, then the number of active cells per unit surface area is improved, but optical cross-talk between adjacent pixels increases
Solution Approach 1:
The patent addresses optical cross-talk not only through lateral separation but also by introducing vertical dimension control through partial-depth second trenches. These trenches create optical barriers at specific depths without requiring complete lateral isolation, enabling effective cross-talk reduction in high-resolution arrays where lateral spacing is minimal.
3Ease of manufacture
If the same manufacturing method is used across the entire array, then manufacturing simplicity is maintained, but variable diode density within the array cannot be achieved
Solution Approach 1:
The patent introduces configurability into the trench structure by allowing selective presence of second trenches in different regions of the array. This enables dynamic adaptation of the manufacturing process to accommodate variable diode density requirements across different zones of the same semiconductor stack, while still using the same basic fabrication techniques.
Data Source
AI summary
Photo-emitting and/or photo-receiving diode array device, comprising:a stack of first and second semiconductor layers doped according to different types;first trenches passing through the stack and surrounding a region of the stack wherein several diodes are formed;dielectric portions arranged in the first trenches and covering lateral flanks of said region over the entire thickness of the second layer and a first part of the thickness of the first layer;first electrically conductive portions arranged in the first trenches and covering the lateral flanks of said region over a second part of the thickness of the first layer, and forming first electrodes of the diodes of said region;at least one second trench partially passing through the first layer and separating the portions of the first layer from the diodes of said region.