PIN Diode Detector Blanket Doping for Edge Leakage Control
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Solution Overview
Problem
PIN diodes suffer from increased current leakage and reduced breakdown voltage due to damage from the dicing process, which affects the performance and reliability of photodetectors.
Innovation Solution
A blanket implantation of dopants with a type opposite to that in the doped wells is applied across the PIN diode, reducing the size of the depletion region outside the detection area and preventing it from reaching the damaged substrate regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the dicing process is used to separate devices on a wafer, then device separation and integration are enabled, but current leakage increases and breakdown voltage decreases due to crystal structure damage
Solution Approach 1:
A compensation doped region is formed in the substrate before the dicing process. This preliminary action creates a region with dopant concentration that compensates for the damage caused by subsequent dicing, preventing current leakage pathways from forming at the diced edges while still allowing device separation to proceed
2Ease of manufacture
If the dicing process is used to separate devices on a wafer, then device separation and integration are enabled, but breakdown voltage decreases due to crystal structure damage
Solution Approach 1:
A compensation doped region is formed in the substrate before the dicing process. This preliminary action creates a region with dopant concentration that compensates for the damage caused by subsequent dicing, maintaining the electrical breakdown characteristics by preventing excessive carrier generation at the diced edges
3Reliability
If blanket doping is applied to reduce depletion region size, then current leakage is reduced and breakdown voltage is maintained, but device complexity increases
Solution Approach 1:
Instead of uniform blanket doping, a compensation doped region is created with specific local properties - it is positioned adjacent to the pixel region and has a dopant concentration specifically designed to compensate for dicing damage. This localized approach with tailored dopant concentration achieves the desired electrical characteristics while minimizing unnecessary complexity
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 reduces current leakage and maintains a consistent breakdown voltage, enhancing the performance and reliability of PIN diodes by preventing the depletion region from expanding into damaged substrate areas.
Implementation Method 1
A blanket implantation of dopants with a type opposite to that in the doped wells is applied across the PIN diode
Implementation Method 2
The detection region is where photons are converted into electrical signals
Data Source
AI summary
A PIN diode detector includes a substrate. The PIN diode detector further includes a plurality of PIN diode wells in a pixel region, wherein each of the plurality of PIN diode wells has a first dopant type. The PIN diode detector further includes a connecting ring well and a plurality of floating ring wells in a peripheral region, wherein the connecting ring well and plurality of floating ring wells have the first dopant type. The PIN diode detector further includes a field stop ring well surrounding the plurality of floating ring wells, wherein the field stop ring well has a second dopant type opposite the first dopant type. The PIN diode detector further includes a blanket doped region. The blanket doped region extends continuously through an entirety of the pixel region and an entirety of the peripheral region, and the blanket doped region has the second dopant type.