Photodetector Substrate Insulating Blocks Reduce Dark Current

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Solution Overview

Problem

Conventional X-ray photodetectors suffer from dark current noise due to electron-hole pairs produced by temperature variations in the photon absorbing layer, which affects detection accuracy.

Innovation Solution

A photodetector substrate design featuring alternately arranged first and second electrodes with insulating blocks between them, replacing the photon absorbing material in gap regions with insulating materials like nylon or polyamidoimide to reduce electron-hole pair generation from temperature variations, and incorporating a photon absorbing layer on top for signal storage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If photon absorbing material is used in gap regions between electrodes, then photon detection capability is maintained, but dark current noise increases due to temperature-induced electron-hole pair generation

Engineering Contradiction:

Improvedark current noiseVSAvoiddetection accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent applies different materials to different regions: photon absorbing material is used in the active detection regions (under electrodes) while insulating material is used in the gap regions between electrodes. This local differentiation allows the device to maintain photon detection capability where needed while eliminating dark current noise in regions where it would interfere with measurements.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The gap regions between adjacent first and second electrodes are segmented and filled with insulating material, separating these regions from the photon absorbing material. This segmentation prevents temperature-induced electron-hole pair generation in the gaps while maintaining photon absorption in the active regions.

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If insulating material is used in gap regions, then dark current noise is reduced, but manufacturing complexity increases due to additional material deposition and patterning steps

Engineering Contradiction:

Improvedark current noiseVSAvoidmanufacturing process complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The insulating material filling process is merged with the existing multi-layer fabrication process. The insulating material is deposited as part of the layered structure construction, and the patterning is integrated with the electrode formation steps, reducing the need for separate dedicated process steps.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The device structure becomes a composite of different materials in different regions: conductive electrodes, photon absorbing material in active regions, and insulating material in gap regions. This composite structure achieves multiple functions simultaneously while using standard materials and processes.

Inventive Principle:

Principle #40Composite materials

3Object-affected harmful factors

If insulating blocks are added between electrodes, then electron-hole pair generation from temperature variations is minimized, but device area increases

Engineering Contradiction:

Improvetemperature-induced noiseVSAvoiddevice footprint

Core Design Contradiction:

Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The harmful photon absorbing material is extracted from the gap regions and replaced with insulating material. This removal of photon absorbing material from non-active regions eliminates the source of temperature-induced noise without requiring additional space, as the insulating material occupies the same gap space.

Inventive Principle:

Principle #2Taking out (Extraction)

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 significantly reduces dark current noise and enhances the signal-noise ratio by minimizing electron-hole pairs produced by temperature variations while maintaining photon detection efficiency.

Implementation Method 1

When a photon having the right wavelength is absorbed by the photon absorbing layer 1, an electron-hole pair is produced.

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

the insulating block spaces apart one of the plurality of first electrodes from an adjacent one of the second electrodes along the first direction... minimizing electron-hole pairs produced by temperature variations

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS10204961B2Photodetector substrate, photodetector having the same, and method of manufacturing thereof

Publication Date: 2019.02.12 BOE TECHNOLOGY GROUP CO LTD

AI summary

The present application discloses a photodetector substrate comprising an array of a plurality of first electrodes; an array of a plurality of second electrodes, and an insulating block. The plurality of first electrodes and the plurality of second electrode are alternately arranged along a first direction, the plurality of first electrodes are disposed spaced apart from the plurality of second electrodes on a same layer; and the insulating block spaces apart at least a pair of adjacent first electrode and second electrode.