Silicon Sensor Intermediate Band Layer for Broadband IR Detection
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Solution Overview
Problem
Existing silicon-based image sensors are limited in their ability to detect electromagnetic radiation with wavelengths greater than 1100 nm, such as short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR), due to the high cost of materials and techniques required for such detection.
Innovation Solution
The introduction of an intermediate band layer comprising a plurality of dopant particles in a silicon-based sensor, which absorbs photons with energies lower than the silicon band gap, forming optically induced minority carriers that can be converted into detectable carriers by an adjacent n-p junction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon-based sensors are used to detect wavelengths greater than 1100 nm, then the cost is reduced, but the detection capability is lost
Solution Approach 1:
The sensor is divided into two functional layers: a photo-sensitive silicon substrate for standard detection and an intermediate band layer for extended wavelength detection. This segmentation allows each layer to specialize in different wavelength ranges, enabling silicon-based sensors to detect wavelengths greater than 1100 nm while maintaining cost effectiveness
Solution Approach 2:
The patent combines silicon substrate with an intermediate band layer containing dopant particles to create a composite sensor structure. This composite material approach enables the sensor to detect a broader wavelength range (including SWIR, MWIR, LWIR) while maintaining the cost advantages of silicon-based technology
2Adaptability or versatility
If intermediate band layer is added to extend wavelength range, then detection capability is improved, but device complexity increases
Solution Approach 1:
The intermediate band layer serves multiple functions: it absorbs photons with energies lower than the silicon band gap, forms optically induced minority carriers, and enables detection across SWIR, MWIR, and LWIR ranges. This multi-functionality extends the wavelength range without requiring separate detection systems for each band
Solution Approach 2:
The intermediate band layer acts as an intermediary between incident photons and the silicon substrate. It absorbs low-energy photons that silicon cannot directly detect, converts them to optically induced minority carriers, and transfers them to the silicon substrate for signal readout, thereby extending detection capability with a single intermediate component
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 enhances the sensitivity and absorption of silicon sensors for electromagnetic radiation across a broader wavelength range, including SWIR, MWIR, and LWIR, without the need for expensive materials, thereby reducing costs and expanding the capabilities of silicon-based sensors.
Implementation Method 1
the intermediate band layer includes a plurality of dopant particles configured to absorb photons having energies lower than the band gap of the silicon sensor to form optically induced minority carriers
Implementation Method 2
the n-p junction may be configured to convert a carrier optically induced in the intermediate band to a carrier in the conduction band or the valence band
Data Source
AI summary
In general, the disclosure describes sensor including an intermediate band layer including a plurality of dopant particles, wherein the intermediate band layer is configured to absorb a portion of incident electromagnetic radiation comprising a first range of wavelengths greater than 1100 nm and form optically induced minority carriers. The sensor also includes a photo-sensitive silicon substrate configured to detect the electromagnetic radiation comprising a second range of wavelengths less than or equal to 1100 nm.