Monolithic Infrared to Visible Light Converter for Silicon Detectors
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Solution Overview
Problem
Infrared detectors and imagers operating beyond 1000 nanometers are not detectable by silicon detectors, leading to bulky and expensive devices due to the need for bump-bonding to integrate detectors with readout circuits.
Innovation Solution
A system that monolithically integrates an infrared light detector and a visible light emitting device, such as an OLED or LED, to directly convert infrared light to visible light within the detectable range of silicon CMOS or CCD detectors, eliminating the need for bump-bonding and enabling high gain through up-conversion of infrared photons to visible photons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If infrared detectors operating beyond 1000 nanometers are integrated with readout circuits using bump-bonding, then detection capability is achieved, but device weight and volume increase significantly
Solution Approach 1:
The patent merges the infrared detector and readout circuit onto a single silicon substrate, eliminating the need for bump-bonding integration. This integration approach maintains detection capability while significantly reducing device weight and volume by removing separate detector components and bonding structures.
Solution Approach 2:
The patent replaces the mechanical bump-bonding integration process with a monolithic semiconductor fabrication approach. By using standard silicon CMOS fabrication techniques to create the detector and readout circuit together, the complex mechanical assembly process is substituted with a streamlined manufacturing method that reduces device complexity and weight.
2Adaptability or versatility
If bump-bonding is used to integrate infrared detectors with readout circuits, then functional integration is achieved, but manufacturing cost increases
Solution Approach 1:
The detector and readout circuit are merged into a single monolithic silicon device, allowing both components to be fabricated simultaneously using standard CMOS processes. This eliminates the need for costly post-fabrication bump-bonding operations and reduces manufacturing complexity.
Solution Approach 2:
The patent changes the fabrication parameter from separate component assembly to integrated monolithic fabrication. By designing the detector and readout circuit to be compatible with the same fabrication process parameters, the manufacturing cost is reduced while maintaining functional integration.
3Device complexity
If silicon detectors are used for infrared wavelengths beyond 1000 nanometers, then detection is limited, but device simplicity is maintained
Solution Approach 1:
The patent changes the detection parameter by engineering the silicon detector's bandgap through doping and structural modifications. This allows standard silicon material to detect infrared wavelengths beyond its natural 1000 nanometer limit, extending detection range while maintaining device simplicity.
Solution Approach 2:
The patent uses composite doping structures within the silicon detector, combining different doped regions to create the necessary bandgap engineering. This allows extended infrared detection capability using standard silicon material rather than requiring exotic semiconductor compounds.
4Adaptability or versatility
If infrared light is directly converted to visible light, then silicon detector compatibility is achieved, but conversion efficiency must be optimized
Solution Approach 1:
The patent optimizes the conversion efficiency parameter by engineering the detector's quantum efficiency through doping profiles and structural design. This ensures that the direct conversion of infrared photons to visible light maintains high efficiency while achieving compatibility with standard silicon detectors.
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 solution significantly reduces the weight, volume, and cost of infrared imagers while providing high gain, especially in low-intensity applications like night vision, by converting infrared light to visible light that can be detected by silicon-based detectors, resulting in a compact and cost-effective imaging solution.
Implementation Method 1
An infrared absorbing layer may have a bandgap energy smaller than about 1.24 electron-volt. An electron-hole pair may be produced as result of the infrared absorbing layer absorbing the infrared light.
Implementation Method 2
In one aspect, a barrier and trap layer may be adapted to simultaneously trap the holes and block electron injection.
Implementation Method 3
The light emitting device may be an organic light emitting diode (OLED), a light emitting diode (LED) or light emitting laser (VCSEL).
Data Source
AI summary
In one aspect, an apparatus for converting light having a first wavelength to a light having a second wavelength is provided. The apparatus includes an interband light detector configured to detect light with the first wavelength, a light emitting device configured to emit light with the second wavelength, and a connector connecting the light detector to the light emitting device. In another aspect, an apparatus includes an absorber layer configured to absorb light having a first wavelength, a barrier and trap layer adjacent the absorber layer, an injector layer adjacent the barrier and trap layer, and an emitting device configured to emit light having a second wavelength. In a further aspect, a method is provided and includes absorbing an input light having a first wavelength, converting the first wavelength to a second wavelength different in size than the first wavelength, and emitting an output light having the second wavelength.