Barrier-Based Position Sensitive Detector Arrays for SWIR-MWIR
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Solution Overview
Problem
Existing position sensitive detectors (PSDs) face challenges in being cost-effective and high-performance, particularly in operating across short wave infrared (SWIR) to mid wave infrared (MWIR) wavelengths, due to the high cost of HgCdTe material and the immaturity and expense of II-VI material fabrication processes, as well as the need for low temperature operation.
Innovation Solution
A position sensitive detector design featuring a substrate with an absorber layer, a barrier layer, and a contact layer, where the barrier layer prevents majority carrier flow, allowing for lateral position sensitivity of incident light, using III-V materials like InAsSb for the absorber and contact layers, and AlAsSb or AlGaSb for the barrier layer, enabling operation from SWIR to MWIR wavelengths and higher temperature operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If HgCdTe infrared material is used for the absorber layer, then high performance is achieved, but the cost becomes very expensive
Solution Approach 1:
The patent changes the material composition parameters by using InAsSb absorber layer with specific indium content (0.1 to 0.5) and Sb content (0.45 to 0.55), combined with AlAsSb or AlGaSb barrier layers. This parameter optimization allows the detector to achieve high performance in the 1-5.25 μm wavelength range while using cheaper III-V materials instead of expensive HgCdTe
Solution Approach 2:
The patent employs composite material structures including InAsSb absorber layer combined with AlAsSb or AlGaSb barrier layers, and InP or InGaAs contact layers. This composite approach leverages the advantages of different materials to achieve both high performance and cost-effectiveness
2Ease of manufacture
If InSb material is used for PSD arrays, then cost is reduced, but operation requires 77 degrees Kelvin and SWIR cutoff occurs
Solution Approach 1:
The patent modifies the material composition by using InAsSb with optimized indium and antimony content ratios, which extends the wavelength coverage to 1-5.25 μm and allows operation at higher temperatures (up to 200K) compared to pure InSb that requires 77K and has SWIR cutoff
Solution Approach 2:
The patent combines InAsSb absorber layer with AlAsSb or AlGaSb barrier layers to create a composite structure that maintains low cost while extending operational versatility to cover both SWIR and MWIR ranges at elevated temperatures
3Ease of manufacture
If InGaAs PN junction-based PSD arrays are used, then commercial availability is achieved, but wavelength coverage is limited to visible to near infrared
Solution Approach 1:
The patent changes the material bandgap parameters by using InAsSb with higher indium content (0.1 to 0.5) compared to standard InGaAs, which extends the detectable wavelength range from visible-NIR to SWIR-MWIR (1-5.25 μm) while maintaining commercial fabrication compatibility
4Adaptability or versatility
If HgCdTe material is used for extended wavelengths, then MWIR coverage is achieved, but cost increases significantly
Solution Approach 1:
The patent optimizes the compositional parameters of InAsSb (indium content 0.1-0.5, Sb content 0.45-0.55) to achieve extended wavelength coverage into MWIR range (up to 5.25 μm) while using cheaper III-V material systems instead of expensive HgCdTe
Solution Approach 2:
The patent creates composite structures with InAsSb absorber layers and AlAsSb/AlGaSb barrier layers that achieve extended wavelength coverage at lower cost by leveraging the material properties of III-V compound semiconductors
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 design achieves high-performance, low-cost PSDs that can operate from 1 to 5.25 μm wavelengths and function at temperatures up to 200 Kelvin, reducing cooling costs and enabling large-format array production on affordable substrates.
Implementation Method 1
the barrier layer prevents a flow of majority carriers from the absorber layer to the contact layer
Implementation Method 2
the position sensitive detector is sensitive to a lateral position between the first contact and the second contact of incident light on the contact layer
Data Source
AI summary
A position sensitive detector includes a substrate, an absorber layer on the substrate, a barrier layer on the absorber layer, a contact layer on the barrier layer, and a first contact and a second contact on the contact layer. The barrier layer prevents a flow of majority carriers from the absorber layer to the contact layer. The position sensitive detector is sensitive to a lateral position between the first contact and the second contact of incident light on the contact layer.