Photodiode Device with Localized Doping for Charge Collection
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Solution Overview
Problem
Current photodiode devices and arrays face limitations in performance metrics such as resolution, signal-to-noise ratio, readout speed, and charge crosstalk, necessitating improvements in their design and structure.
Innovation Solution
A photodiode device with a lightly doped semiconductor base and heavily doped electrode regions, along with protruding structures connected to the second electrode region, is designed to enhance charge collection and reduce crosstalk by optimizing the electric field distribution and carrier collection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the photodiode device uses conventional doping structures, then the manufacturing process is simple, but the charge collection time is insufficient and photoresponse is weak
Solution Approach 1:
The patent applies local quality by creating a non-uniform doping structure where the electrode region has different doping concentration and type compared to the base region. Specifically, the electrode region is doped with a doping concentration of 1×10^16 to 1×10^18 atoms/cm³, which is lower than the base region's 1×10^14 to 1×10^16 atoms/cm³, and with opposite doping type (n-type electrode in p-type base or vice versa). This localized variation in doping properties optimizes charge collection at the electrode interface without requiring complex overall structural changes.
Solution Approach 2:
The patent employs parameter changes by systematically varying the doping concentration and doping type parameters in different regions of the photodiode. The base region maintains a doping concentration of 1×10^14 to 1×10^16 atoms/cm³, while the electrode region uses 1×10^16 to 1×10^18 atoms/cm³. This parameter optimization extends charge collection time and enhances photoresponse without significantly increasing device complexity.
2Reliability
If the photodiode device enhances charge collection efficiency, then photoresponse is improved, but charge crosstalk between pixels increases
Solution Approach 1:
The patent applies local quality by creating distinct doping regions with specific properties that confine charge collection to local areas. The electrode region's specialized doping (1×10^16 to 1×10^18 atoms/cm³, opposite type to base) creates localized electric field distributions that guide carriers to their respective electrodes without spreading to adjacent pixels. This local optimization improves photoresponse while maintaining pixel isolation.
Solution Approach 2:
The patent converts the potential harmful effect of extended charge collection (which could cause crosstalk) into a benefit by using the extended collection time to improve photoresponse. The optimized doping structure ensures that the extended collection pathway remains confined within each pixel's electrode region, transforming what could be a source of crosstalk into enhanced charge collection efficiency.
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
The solution effectively increases charge collection time, enhances photoresponse, and reduces charge crosstalk between pixels, leading to improved light detection performance.
Implementation Method 1
detect incident light (e.g., directly incident light rays, or visible light rays generated by X-rays in a scintillator) by the incident light ionizing atoms in a semiconductor and thereby generating unbalanced carriers
Data Source
Figure 1A
Figure 1B~1C
Figure 2A~2C(b)
AI summary
A photodiode device and a photodiode detector are provided. According to an embodiment, the photodiode device may include a first type lightly doped semiconductor base including a first surface and a second surfaces opposite to each other, a first electrode region being first type heavily doped and disposed on the first surface of the semiconductor base, a second electrode region being second type heavily doped and disposed on the second surface of the semiconductor base, wherein the first surface is a light incident surface.