Dark current optimization designs for mesa and planar type processed short wavelength infrared photodetectors

Dolaş, Muhammet Halit
This thesis aims to report novel designs to achieve lower dark current values for modified pin heterojunction InGaAs/InP SWIR photodiodes for both mesa and planar type production methodologies.Mesa type studies covernovel passivation methodology based on a fully depleted thin p-InP layer. Mesastructured detectors are targeted due to their competitive advantages for applications such as multicolor/hyperspectral imaging. Test detector pixels with different perimeter/area ratios are fabricated with and without etching the thin InP passivation layer between pixels in order to comparatively examine passivating behavior. I-V characteristics of the test detectors are measured at room temperature. Based on the results from differentlysized pixel groups, bulk and surface dark current components are separated. Results show that thin InP layer decreases dark current by a factor of 3 while increasing photo current due to higher carrier collection efficiencyPlanar type studies withdeveloping novel epilayer structures,junction depth optimization and successful suppression of surface and bulk generation and recombination (GR) dark current components resulted in diffusion current limited high performance planar type SWIR detectors. For 15 μm pixel pitch, we obtained 12fA pixel dark current at room temperature (~26°C) and 1.08 A/W responsivity (at 1.55 μm) that is corresponding 86% quantum efficiency (QE). Dark current modeling analysis is performed based on bias dependency of diffusion, GR and tunneling current components. Results show excellent match with experimental data.Utilizingthe developed planar type detectors with the state-of-the-art performance, post process optimizations also completed which result high performance megapixel SWIR imaging sensorswith record level operability.


Fully Depleted InP Nano-Layer for In-Device Passivation of InGaAs SWIR Detectors
Dolas, M. Halit; Kocaman, Serdar (2017-12-01)
We designed a p-n InGaAs/InP heterojunction photodiode with a novel passivation approach that employs a thin and fully depleted in-device (embedded in the p-n structure) p-InP layer. We comparatively characterized mesa-type detector pixels and experimentally observed expected passivating behavior. Characterization results under illumination indicated that fully depleted p-InP layer increases photo-current as well due to increasing device active area. Dark current analysis of detector pixels with different a...
Low dark current diffusion limited planar type InGaAs photodetectors
m halit, dolaş; ateşal, okan; çalışkan, m deniz; Bek, Alpan; ÖZBAY, EKMEL (2019-09-09)
In this work, we design and produce 1280x1024 format InGaAs based planar type detectors with 15µm pixel pitch. We have obtained diffusion current limited low dark current (~10fA) and high responsivity (1.08A/W at 1.55µm) values at room temperature conditions. Moreover, dark current modeling is performed using diffusion, generation & recombination (GR) and trap assisted tunneling (TAT) current mechanisms. Ideality factor is extracted from forward bias characteristics. Excellent match between modeling and exp...
Dark current mechanisms and passivation of InAsSb infrared photodiodes on alternative substrates
Ersagun, Özlem; Beşikci, Cengiz; Department of Electrical and Electronics Engineering (2005)
This thesis reports a detailed characterization of indium arsenide antimonide (InAs1- xSbx) photodetectors grown on gallium arsenide (GaAs) substrate by molecular beam epitaxy. A combination of polyimide and sulphur and a single layer of polyimide were used as passivation films in this study. Two different epilayer structures were used for assessing the detector performance and comparing the above passivation layers. For the first structure, the optical measurements revealed that Sb mole fraction was 0.13 a...
Low-Cost LWIR-Band CMOS Infrared (CIR) Microbolometers for High Volume Applications
Akın, Tayfun (2020-01-01)
This paper provides an overview of the studies and the current status for the development of a novel, low-cost, and CMOS foundry compatible approach for implementing microbolometers with standard CMOS and simple post-CMOS subtractive MEMS processes. This CMOS infrared detector technology is shortly called as the CMOS IR (CIR) technology, and it can be used to implement Focal Plane Arrays (FPAs) for infrared imaging in the LWIR-band (8-12 mu m wavelength). Post-CMOS processes require only one mask lithograph...
Topological constraints on HMO heteroatom parameters
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Citation Formats
M. H. Dolaş, “Dark current optimization designs for mesa and planar type processed short wavelength infrared photodetectors,” Ph.D. - Doctoral Program, Middle East Technical University, 2021.