Silicon Photomultiplier Layout With STI Quenching Resistor
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Solution Overview
Problem
Existing silicon photomultiplier tubes face challenges with increased cost and reduced photon detection efficiency due to the need for additional area occupied by quenching resistors, which affects their integration and competitiveness.
Innovation Solution
The silicon photomultiplier tube design features a quenching resistor located on the top surface of a shallow trench isolation, allowing for reduced chip area usage, improved integration, and enhanced photon detection efficiency by arranging the first and second electrode regions on either side of the trench with the photosensitive layer below the first electrode region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the quenching resistor is placed on the silicon substrate surface, then the photomultiplier tube can function properly, but the chip area increases and integration is reduced
Solution Approach 1:
The quenching resistor is moved from the two-dimensional silicon substrate surface to the three-dimensional structure by forming it on the shallow trench isolation layer, effectively utilizing the vertical dimension to reduce the horizontal area occupied on the chip surface
Solution Approach 2:
The quenching resistor is nested within the shallow trench isolation structure, placing it inside the existing isolation region rather than requiring separate dedicated space, thereby improving area utilization
2Reliability
If the quenching resistor occupies additional area, then the photomultiplier tube can operate, but the manufacturing cost increases
Solution Approach 1:
The quenching resistor function is merged with the shallow trench isolation structure, combining two previously separate elements into one integrated structure, which reduces the total component count and manufacturing complexity
Solution Approach 2:
The shallow trench isolation structure serves dual purposes: electrical isolation and housing the quenching resistor, making the structure multi-functional and eliminating the need for separate quenching resistor areas
3Reliability
If the quenching resistor occupies additional area, then the photomultiplier tube can function, but the photon detection efficiency is reduced
Solution Approach 1:
By relocating the quenching resistor to the shallow trench isolation layer in the vertical dimension, the horizontal area available for light-sensitive regions is maximized, thereby improving photon detection 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
This design reduces the overall area and cost of the silicon photomultiplier tube while allowing for adjustable photon detection efficiency by controlling the size of the first electrode region, thereby improving the device's integration and performance.
Implementation Method 1
a photosensitive layer is formed in the silicon substrate at a bottom of the first electrode region; photons enter the photosensitive layer from a front side of the first electrode region to achieve photo sensing
Implementation Method 2
the first electrode region, the photosensitive layer and the second electrode region form a Geiger mode avalanche photodiode
Data Source
AI summary
This application discloses a unit structure of a silicon photomultiplier tube, including a first conductive type heavily doped first electrode region located on a first side of the shallow trench isolation, a second conductive type heavily doped second electrode region located on a second side, and a quenching resistor located on a top surface of the shallow trench isolation. A photosensitive layer is formed in the silicon substrate at bottoms of the first electrode region, the shallow trench isolation and the second electrode region. The first electrode region, the photosensitive layer and the second electrode region form a Geiger mode avalanche photodiode. A first end of the quenching resistor is connected to the first electrode region through a first metal interconnect structure. A second end of the quenching resistor is connected to a first electrode. The second electrode region is connected to a second electrode.