Plasmonic Schottky NIR Sensor With CMOS Readout Integration
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Solution Overview
Problem
Silicon-based photodetectors are limited in spectral coverage beyond 1100 nm and non-silicon detectors are not easily integrated with CMOS-based readout circuits, constraining detector absorption and integration capabilities.
Innovation Solution
A CMOS compatible near-infrared sensor using surface plasmons to generate hot electron carriers, integrated with CMOS readout technology, employing gratings made of metals like aluminum or platinum, and incorporating CMOS sample and hold and ADC circuits for high sensitivity and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If non-silicon detectors are used to extend spectral coverage beyond 1100 nm, then spectral responsivity is improved, but integration with CMOS-based readout circuits becomes difficult
Solution Approach 1:
The patent combines non-silicon detector materials (such as InGaAs) with CMOS readout circuits by integrating the detector layer over a CMOS substrate. This merging approach allows the system to achieve extended spectral coverage while maintaining compatibility with standard CMOS processing, thereby resolving the contradiction between spectral responsivity and integration capability
Solution Approach 2:
The patent employs composite material structures where non-silicon detector materials are deposited on CMOS substrates to create a hybrid device. This composite approach enables the system to leverage the spectral detection capabilities of non-silicon materials while retaining the circuit integration advantages of CMOS technology
2Ease of manufacture
If silicon-based photodetectors are used for integration with CMOS circuits, then ease of manufacture is improved, but spectral coverage beyond 1100 nm is limited
Solution Approach 1:
The patent segments the detector structure into distinct functional layers: a CMOS circuit substrate and an overlaying non-silicon detector layer. This segmentation allows each layer to be optimized independently - the CMOS layer for circuit integration and the non-silicon layer for extended spectral coverage - while maintaining overall system compatibility
3Adaptability or versatility
If surface plasmon-based photodetectors are used to achieve wide spectral responsivity, then spectral coverage is improved, but noise level increases
Solution Approach 1:
The patent introduces an intermediary layer or structure between the surface plasmon generation region and the detection region that filters or modulates the plasmon-induced carriers. This intermediary element allows the system to maintain wide spectral responsivity from surface plasmon excitation while reducing the noise associated with direct plasmon detection
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
Enables wide spectral responsivity in the near-infrared range and integration with CMOS-based readout technology, achieving high photocurrent sensitivity and low noise detection.
Implementation Method 1
surface plasmon-based photodetectors that include: a silicon substrate; a grating in contact with a surface of the silicon substrate, in which the grating forms a Schottky diode with the semiconductor substrate
Implementation Method 2
a grating in contact with a surface of the silicon substrate, in which the grating forms a Schottky diode with the semiconductor substrate
Implementation Method 3
Near-infrared detectors include photodetectors that are capable of detecting light in the near-infrared region of the electromagnetic spectrum
Data Source
AI summary
A surface plasmon-based photodetector includes: a silicon substrate; a grating in contact with a surface of the silicon substrate, in which the grating forms a Schottky diode with the semiconductor substrate; and a complementary-metal-oxide-semiconductor (CMOS) sample and hold stage as well as an analog-to-digital circuit (ADC) in the silicon substrate and arranged to detect electrical current generated at the Schottky diode.