Schottky Photodetector Structure With Tunneling Barrier for Low Dark Current
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Solution Overview
Problem
Conventional silicon-based photodetectors have limitations in detecting near-infrared and short-wavelength infrared light due to low light absorption rates and high dark current issues, which are exacerbated by the difficulty in synthesizing and integrating materials like Ge or InGaAs on silicon substrates, leading to high costs and performance limitations.
Innovation Solution
A photodetector design incorporating a semiconductor layer, a conductive layer forming a Schottky junction, and a tunneling barrier layer with a metal oxide semiconductor, which blocks dark current and increases the Schottky barrier thickness, allowing for wide wavelength band detection from visible to infrared light while reducing dark current through careful selection of materials and energy levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If silicon-based P-N junction is used for visible light detection, then quantum efficiency is high (up to 80%), but detection capability in near-infrared and short-wavelength infrared bands is poor due to low light absorption rate
Solution Approach 1:
The patent employs a composite structure combining silicon substrate with Ge or InGaAs materials to create a photodetector that can detect both visible and infrared light. The silicon layer handles visible light detection while the Ge/InGaAs layer detects infrared wavelengths, achieving wide spectral coverage without sacrificing detection efficiency in either band
Solution Approach 2:
The photodetector is divided into multiple functional layers with different materials optimized for specific wavelength ranges. The silicon-based P-N junction detects visible light while the additional Ge or InGaAs layers detect near-infrared and short-wavelength infrared light, allowing each segment to operate at its optimal performance level
2Adaptability or versatility
If materials like Ge or InGaAs are used to detect infrared light, then detection capability in near-infrared and short-wavelength infrared bands is improved, but manufacturing cost increases and integration on silicon substrate becomes difficult
Solution Approach 1:
The patent uses silicon as an intermediary substrate that facilitates the integration of Ge or InGaAs materials. The silicon-based P-N junction structure serves as a compatible foundation that enables the addition of infrared-sensitive materials while maintaining manufacturability and reducing integration complexity compared to direct integration on other substrates
3Ease of manufacture
If conventional silicon-based photodetector structure is used, then manufacturing cost is low, but dark current is high which limits performance
Solution Approach 1:
The patent modifies key parameters of the silicon-based P-N junction structure, including doping concentrations, layer thicknesses, and material compositions, to optimize the balance between manufacturing cost and dark current suppression. By carefully adjusting these parameters, the design achieves lower dark current while maintaining cost-effectiveness and compatibility with existing silicon fabrication processes
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 enables efficient detection of a wide range of light wavelengths with reduced dark current, lower manufacturing costs, and faster switching capabilities compared to traditional P-N junction structures, improving the performance and efficiency of photodetectors and image sensors.
Implementation Method 1
a tunneling barrier layer between the semiconductor layer and the conductive layer, wherein the tunneling barrier layer may be configured to block a dark current between the semiconductor layer and the conductive layer
Implementation Method 2
a conductive layer forming a Schottky junction with the semiconductor layer
Implementation Method 3
Schottky barrier photodetector
Data Source
AI summary
A photodetector, including: a semiconductor layer, a conductive layer forming a Schottky junction with the semiconductor layer, and a tunneling barrier layer between the semiconductor layer and the conductive layer, wherein the tunneling barrier layer may be configured to block a dark current between the semiconductor layer and the conductive layer.