Infrared Detector Barrier Structure for Low Dark Current
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Solution Overview
Problem
Short-wave infrared detectors using conventional PIN structures face challenges in reducing dark current due to increased defects in high In composition materials, leading to a dominant generation-recombination mechanism, which is not effectively addressed by nBn unipolar barrier structures.
Innovation Solution
A new infrared detector structure featuring a barrier composite layer with an intrinsic, field control, and barrier layer of wide bandgap semiconductor materials, forming a PIN structure that transfers the depletion layer into the wide bandgap intrinsic layer, thereby suppressing generation-recombination current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the composition of In in the absorption layer is increased to extend the cut-off wavelength, then the spectral response range is improved, but the dark current increases due to generation-recombination mechanism
Solution Approach 1:
A wide bandgap intrinsic layer is introduced as an intermediary between the N-type absorption layer and the P-type contact layer. This intrinsic layer acts as a mediator that suppresses the generation-recombination mechanism responsible for dark current, while allowing the absorption layer to maintain high In composition for extended spectral response. The intrinsic layer effectively decouples the conflicting requirements of high In content and low dark current.
Solution Approach 2:
The detector employs a composite structure combining narrow bandgap InGaAs absorption layer with wide bandgap intrinsic and P-type layers. This composite material approach allows each layer to perform its specific function: the narrow bandgap layer provides extended spectral response through high In composition, while the wide bandgap layers suppress dark current through their material properties, achieving both objectives simultaneously.
2Ease of manufacture
If a conventional PIN structure is used in InGaAs detectors, then the manufacturing process is simple, but the dark current cannot be effectively suppressed due to the narrow bandgap of the absorption layer
Solution Approach 1:
The conventional PIN structure is segmented into functional zones: an N-type absorption layer for photon detection, a wide bandgap intrinsic layer for dark current suppression, and P-type contact layers for carrier collection. This segmentation allows each layer to be optimized independently - the absorption layer can use high In composition for extended response while the intrinsic layer suppresses dark current, maintaining manufacturing simplicity through sequential epitaxial growth.
Solution Approach 2:
The invention changes the bandgap parameter of the intermediate layer from narrow (conventional PIN) to wide bandgap (intrinsic layer). This parameter change fundamentally alters the dark current mechanism by suppressing generation-recombination in the intrinsic layer, while the absorption layer maintains its narrow bandgap properties for extended spectral response. The doping concentration parameters are also optimized in each layer to achieve low dark current.
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 significantly reduces dark current by transferring the depletion region to the wide bandgap intrinsic layer, improving carrier transport and reducing surface leakage, making it suitable for InGaAs and InP-based T2SL detectors.
Implementation Method 1
the depletion layer of the infrared detector transferred into the wide bandgap intrinsic layer, thereby effectively suppressing the generation-recombination current of the detector
Implementation Method 2
an absorption layer and a barrier composite layer between the first contact layer and the second contact layer; the absorption layer is an N-type doped narrow bandgap semiconductor material layer
Data Source
AI summary
An infrared detector and a manufacturing method for the infrared detector are provided. The infrared detector includes a first contact layer, a second contact layer, and an absorption layer and a barrier composite layer between the first contact layer and the second contact. The barrier composite layer includes an intrinsic layer, a field control layer and a barrier layer which are adjacent in sequence and are all of wide bandgap semiconductor materials. The intrinsic layer is adjacent to the absorption layer made of a narrow bandgap semiconductor material. The doping type of the absorption layer is N-type doping, and the field control layer and the barrier layer are both P-type doping, so that the barrier composite layer and the absorption layer can form a PIN structure, with the depletion layer of the infrared detector transferred into the wide bandgap intrinsic layer, thereby effectively suppressing a generation-recombination current of the detector.