Photonic Demodulator Intermediate Electrodes for NIR Contrast and Bandwidth
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Solution Overview
Problem
Current-assisted photonic demodulators suffer from limitations in AC demodulation contrast, parasitic light sensitivity, and bandwidth, particularly when detecting near-infrared light radiation.
Innovation Solution
Incorporation of intermediate electrodes, spaced apart from the first face by a non-zero distance, between p-doped and n-doped regions, along with optimized doping depths and configurations, enhances electrical isolation and reduces electron recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If intermediate electrodes are added between p-doped and n-doped regions, then demodulation contrast and bandwidth are improved, but device complexity increases
Solution Approach 1:
The patent introduces intermediate electrodes as mediator elements positioned between the p-doped and n-doped regions. These intermediate electrodes serve as a bridge to optimize the electric field distribution and carrier collection efficiency, thereby improving demodulation contrast and bandwidth without requiring fundamental redesign of the basic detector structure.
Solution Approach 2:
The detector structure is segmented into distinct functional zones with p-doped regions, n-doped regions, and intermediate electrodes positioned at specific intervals. This segmentation allows independent optimization of each zone's function while maintaining overall system performance, enabling improved demodulation characteristics through structured spatial division.
2Speed
If intermediate electrodes are added between p-doped and n-doped regions, then bandwidth is improved, but device complexity increases
Solution Approach 1:
The intermediate electrodes act as mediator structures that facilitate faster carrier collection and reduce transit time. By positioning these electrodes strategically between the doped regions, the patent enables improved bandwidth performance through enhanced electric field management without requiring complete restructuring of the detector architecture.
Solution Approach 2:
The intermediate electrodes extend in the vertical dimension above the p-doped and n-doped regions, creating a three-dimensional electrode structure. This dimensional addition allows for optimized electric field distribution in the vertical space, improving carrier collection speed and bandwidth without increasing the lateral footprint of the device.
3Area of stationary object
If p-doped regions are positioned closer to the central zone, then fill factor is improved, but parasitic light sensitivity increases
Solution Approach 1:
The patent applies different doping concentrations and electrode configurations to specific local regions. The p-doped regions are optimized with specific doping levels and geometries tailored to their local position, allowing the fill factor to be maximized in central areas while parasitic sensitivity is controlled through localized electric field management and intermediate electrode positioning.
Solution Approach 2:
Intermediate electrodes are positioned as mediator structures between the p-doped regions and the central detection zone. These electrodes create localized electric field gradients that guide carriers away from parasitic collection paths while maintaining efficient collection from the central zone, thereby reducing parasitic light sensitivity without sacrificing fill factor.
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
Improves demodulation contrast, reduces parasitic light sensitivity, and increases bandwidth by accumulating majority carriers under the dielectric passivation layer, leading to enhanced performance in detecting near-infrared radiation.
Implementation Method 1
An electrical potential difference is applied between the p+ regions, which generates a drift electric field in the detection portion. Thus, when light radiation is absorbed in the detection portion, an electron-hole pair is generated, then the photogenerated hole propagates under the effect of the drift field in the direction of the p+ doped region having the lowest electrical potential, whereas the photogenerated electron is directed in the direction of the opposite p+ doped region
Implementation Method 2
improves demodulation contrast, reduces parasitic light sensitivity, and increases bandwidth by accumulating majority carriers under the dielectric passivation layer
Implementation Method 3
when light radiation is absorbed in the detection portion, an electron-hole pair is generated
Data Source
AI summary
A current-assisted photonic demodulator includes a detection portion having two doped modulation regions and two doped collection regions, lying flush with a first face covered by a dielectric layer. Electrodes pass through the dielectric layer and come into contact with the doped regions. In addition, intermediate electrodes partly pass through the dielectric layer and are spaced apart from the first face by a non-zero distance, each being located, in projection in a main plane, between one of the doped modulation regions and the adjacent doped collection region.