High-resolution imaging in ultraviolet (UV) bands has many applications in defense and commercial systems. The shortest wavelength is desired for increased spatial resolution, which allows for small pixels and large formats. In past work, UV avalanche photodiodes (APDs) have been reported as discrete devices demonstrating gain. The next frontier is to develop UVAPD arrays with high gain to demonstrate highresolution imaging. We will discuss a model that can predict sensor performance in the UV band using APDs with various gain and other parameters for a desired UV band of interest. Signal-to-noise ratios (SNRs) can be modeled from illuminated targets at various distances with high resolution under standard atmospheric conditions in the UV band and the solar-blind region using detector arrays with unity gain and with high-gain APDs. We will present recent data on the GaN-based APDs for their gain, detector response, dark current noise, and 1/f noise. We will discuss various approaches and device designs that are being evaluated for developing APDs in wide-bandgap semiconductors. The paper will also discuss the state of the art in UVAPDs and the future directions for small unit cell size and gain in the APDs.
Low cost IR Sensors are needed for a variety of Defense and Commercial Applications as low cost imagers for various Army and Marine missions. SiGe based IR Focal Planes offers a low cost alternative for developing wafer-level shortwave infrared micro-camera that will not require any cooling and can operate in the Visible-NIR band. The attractive features of SiGe based IRFPA’s will take advantage of Silicon based technology, that promises small feature size and compatibility with the low power silicon CMOS circuits for signal processing. SiGe technology offers a low cost alternative for developing Visible-NIR sensors that will not require any cooling and can operate from 0.4- 1.7 microns. The attractive features of SiGe based IRFPA’s will take advantage of Silicon based technology that can be processed on 12-inch silicon substrates, that can promise small feature size and compatibility with the Silicon CMOS circuit for signal processing. In this paper, we will discuss the design and development of Wafer-Level Short Wave Infrared (SWIR) Micro-Camera. We will discuss manufacturing approaches and sensor configurations for short wave infrared (SWIR) focal plane arrays (FPAs) that significantly reduce the cost of SWIR FPA packaging, optics and integration into micro-systems.
High resolution imaging in the UV band has a lot of applications in defense and commercial systems. The
shortest wavelength is desired for spatial resolution which allows for small pixels and large formats.
UVAPD's have been demonstrated as discrete devices demonstrating gain. The next frontier is to develop UV
APD arrays with high gain to demonstrate high resolution imaging.
We will discuss model that can predict sensor performance in the UV band using APD's with various gain
and other parameters for a desired UV band of interest. SNR's can be modeled from illuminated targets at
various distances with high resolution under standard atmospheres in the UV band and the solar-blind region
using detector arrays with unity gain and with high-gain APD's.
We will present recent data on the GaN based APD's for their gain, detector response, dark current noise and
the 1/f noise. We will discuss various approaches and device designs that are being evaluated for developing
APD's in wide band gap semiconductors. The paper will also discuss state-of-the-art in UV APDs and the
future directions for small unit cell size and gain in the APD's.
High resolution imaging in the UV band has a lot of applications in Defense and Commercial
Applications. The shortest wavelength is desired for spatial resolution which allows for small pixels and
large formats. UVAPD's have been demonstrated as discrete devices demonstrating gain. The next frontier is
to develop UV APD arrays with high gain to demonstrate high resolution imaging. We also disuses our recent
efforts on development of APD's using MOCVD of GaN/ AlGaN.
We present an analytical model that can predict sensor performance in the UV band using p-i-n or
APD detectors with and without gain and other detector and sensor parameters for a desired UV band of
interest. SNR's can be modeled from illuminated targets at various distances with high resolution under
standard MODTRAN atmospheres in the UV band using detector arrays with unity gain and with high gain
APD along with continuous or pulsed UV lasers.
Next Generation EO/IR focal plane arrays using nanostructure materials are being developed for a variety
of Defense Applications including Unattended Ground Sensor Applications. Several different
nanomaterials are being evaluated for these applications. These include ZnO nanowires that have
demonstrated large signal to noise ratio as a wide band gap nanostructure material in the UV band.
Similarly, the work is under way using Carbon Nanotubes (CNT) for a high speed detector and focal plane
array as bolometer for IR bands of interest, which can be implemented for the unattended ground sensor
applications.
In this paper, we will discuss the sensor design and model predicting performance of an EO/IR focal plane
array that can cover the UV to IR bands of interest. The model can provide a robust means for comparing
performance of the EO/IR FPA's and Sensors that can operate in the UV, Visible-NIR (0.4-1.8μ), SWIR
(2.0-2.5μ), MWIR (3-5μ), and LWIR bands (8-14μ). This model can be used as a tool for predicting
performance of nanostructure arrays under development. We will also discuss our results on growth and
characterization of ZnO nanowires and CNT's for the next generation sensor applications. Several
approaches for compact energy harvesting using nanostructures will be discussed.
SiGe based focal plane arrays offer a low cost alternative for developing visible- near-infrared focal plane arrays that
will cover the spectral band from 0.4 to 1.6 microns. The attractive features of SiGe based foal plane arrays take
advantage of silicon based technology that promises small feature size, low dark current and compatibility with the
low power silicon CMOS circuits for signal processing. This paper discusses performance characteristics for the
SiGe based VIS-NIR Sensors for a variety of defense and commercial applications using small unit cell size and
compare performance with InGaAs, InSb, and HgCdTe IRFPA's. We present results on the approach and device
design for reducing the dark current in SiGe detector arrays. The electrical and optical properties of SiGe arrays at
room temperature are discussed. We also discuss future integration path for SiGe devices with Si-MEMS
Bolometers.
High resolution imaging in the UV band has a lot of applications in Defense and Commercial
Applications. The shortest wavelength is desired for spatial resolution which allows for small pixels and
large formats. UVAPD's have been demonstrated as discrete devices demonstrating gain. The next frontier is
to develop UV APD arrays with high gain to demonstrate high resolution imaging. We also disuses our recent
efforts on development of APD's using MOCVD of GaN/ AlGaN.
We present an analytical model that can predict sensor performance in the UV band using p-i-n or
APD detectors with and without gain and other detector and sensor parameters for a desired UV band of
interest. SNR's can be modeled from illuminated targets at various distances with high resolution under
standard MODTRAN atmospheres in the UV band using detector arrays with unity gain and with high gain
APD along with continuous or pulsed UV lasers.
SiGe based focal plane arrays offer a low cost alternative for developing visible- near-infrared focal plane
arrays that will cover the spectral band from 0.4 to 1.6 microns. The attractive features of SiGe based foal
plane arrays take advantage of silicon based technology that promises small feature size, low dark current
and compatibility with the low power silicon CMOS circuits for signal processing. This paper will discuss
performance characteristics for the SiGe based VIS-NIR Sensors for a variety of defense and commercial
applications using small unit cell size and compare performance with InGaAs, InSb, and HgCdTe
IRFPA's. We will present results on the approach and device design for reducing the dark current in SiGe
detector arrays. We will discuss electrical and optical properties of SiGe arrays at room temperature and
as a function of temperature. We will also discuss future integration path for SiGe devices with other
Silicon-based technology for defense and Commercial Applications.
Next Generation EO/IR focal plane arrays using nanostructure materials are being developed for a variety of Defense Applications including Unattended Ground Sensor Applications. These include ZnO nanowires that have demonstrated large signal to noise ratio as a wide band gap nanostructure material in the UV band. Similarly, the work is under way using Carbon Nanotubes (CNT) for a high speed detector and focal plane array as bolometer for IR bands of interest, which can be implemented for the unattended ground
sensor applications.
In this paper, we will discuss the sensor design and model predicting performance of an EO/IR focal plane array that can cover the UV to IR bands of interest. The model can provide a robust means for comparing performance of the EO/IR FPA's and Sensors that can operate in the UV, Visible-NIR (0.4-1.8μ), SWIR (2.0-2.5μ), MWIR (3-5μ), and LWIR bands (8-14μ). This model can be used as a tool for predicting performance of nanostructure arrays under development. We will also discuss our results on growth and
characterization of ZnO nanowires and CNT's for the next generation sensor applications.
EO/IR Sensors and imagers using nanostructure based materials are being developed for a variety
of Defense Applications. In this paper, we will discuss recent modeling effort and the
experimental work under way for development of next generation carbon nanostructure based
infrared detectors and arrays. We will discuss detector concepts that will provide next generation
high performance, high frame rate, and uncooled nano-bolometer for MWIR and LWIR bands.
The critical technologies being developed include carbon nanostructure growth, characterization,
optical and electronic properties that show the feasibility for IR detection. Experimental results on
CNT nanostructures will be presented. We will discuss the path forward to demonstrate
enhanced IR sensitivity and larger arrays.
SiGe based focal plane arrays offer a low cost alternative for developing visible- near-infrared focal plane arrays that
will cover the spectral band from 0.4 to 1.6 microns. The attractive features of SiGe based foal plane arrays take
advantage of silicon based technology that promises small feature size, low dark current and compatibility with the
low power silicon CMOS circuits for signal processing. This paper will discuss performance characteristics for the
SiGe based VIS-NIR Sensors for a variety of defense and commercial applications using small unit cell size and
compare performance with InGaAs, InSb, and HgCdTe IRFPA's. We will present results on the approach and
device design for reducing the dark current in SiGe detector arrays. We will discuss electrical and optical properties
of SiGe arrays at room temperature and as a function of temperature. We will also discuss future integration path for
SiGe devices with Si-MEMS Bolometers.
High resolution imaging in UV band has a lot of applications in Defense and Commercial systems. The
shortest wavelength is desired for spatial resolution which allows for small pixels and large formats.
UVAPD's have been demonstrated as discrete devices demonstrating gain. The next frontier is to develop UV
APD arrays with high gain to demonstrate high resolution imaging.
We will discuss an analytical model that can predict sensor performance in the UV band using p-i-n or APD
detectors with and without gain and other detector and sensor parameters for a desired UV band of interest.
SNR's can be modeled from illuminated targets at various distances with high resolution under standard
MODTRAN atmospheres in the UV band and the solar blind region using detector arrays with unity gain
and with high gain APD along with continuous or pulsed UV lasers.
The performance can be determined by the signal level which results from the UV laser return energy (laser
power, beam divergence, target reflectance and atmospheric transmittance), the optics f/number, the response
of the detector (collection area, quantum efficiency, fill factor and gain), and the total noise which will be the
sum of the dark current noise, the scene noise, and the amplifier noise. We also discuss trades as a function
of detector response, dark current noise and the 1/f noise. We also present various approaches and device
designs that are being evaluated for developing APD's in wide band gap semiconductors. The paper also
discusses current state of the art in UV APD and the future directions for small unit cell size and gain in the
APD's.
EO/IR Sensors have been developed for a variety of Military Systems Applications.
These include UV, Visible, SWIR, MWIR and LWIR Sensors. The conventional SWIR Sensors
using InGaAs Focal Plane Array (FPA) can operate in 0.4 - 1.8 micron region. Similarly, MWIR
Sensors use InSb and HgCdTe based FPA's that are sensitive in 3-5 and 8-14 micron region.
DOD investments in the last 10 years have provided the necessary building blocks for the IR
Sensors that are being deployed in the field.
In this paper, we discuss recent developments and work under way to develop Next
Generation nanostructure based EO/IR detectors that can potentially cover UV, Visible and IR
regions of interest. The critical technologies being developed include ZnO nanostructures with
wide band gap for UV detection and Carbon Nanostructures that have shown the feasibility for IR
detection. Experimental results on ZnO based nanostructures demonstrate enhanced UV
sensitivity and path forward for larger arrays. Similarly, recent works on carbon nanostructures
have shown the feasibility of IR detection. Combining the two technologies in a sensor can
provide multispectral capability.
SiGe based Focal Plane Arrays offer a low cost alternative for developing visible- NIR focal plane arrays
that will cover the spectral band from 0.4 to 1.6 microns. The attractive features of SiGe based IRFPA's
will take advantage of Silicon based technology, that promises small feature size, low dark current and
compatibility with the low power silicon CMOS circuits for signal processing. This paper discusses
performance comparison for the SiGe based VIS-NIR Sensor with performance characteristics of InGaAs,
InSb, and HgCdTe based IRFPA's.
Various approaches including device designs are discussed for reducing the dark current in SiGe detector
arrays; these include Superlattice, Quantum dot and Buried junction designs that have the potential of
reducing the dark current by several orders of magnitude. The paper also discusses approaches to reduce
the leakage current for small detector size and fabrication techniques. In addition several innovative
approaches that have the potential of increasing the spectral response to 1.8 microns and beyond.
Next Generation EO/IR Sensors using Nanostructures are being developed for a variety of Defense
Applications. In addition, large area IRFPA's are being developed on low cost substrates. In this paper, we will discuss
the capabilities of a EO/IR Sensor Model to provide a robust means for comparing performance of infrared FPA's and
Sensors that can operate in the visible and infrared spectral bands that coincide with the atmospheric windows - UV,
Visible-NIR (0.4-1.8μ), SWIR (2.0-2.5μ), MWIR (3-5μ), and LWIR (8-14μ).
The model will be able to predict sensor performance and also functions as an assessment tool for single-color
and for multi-color imaging. The detector model can also characterize ZnO, Si, SiGe, InGaAs, InSb, HgCdTe and
Nanostructure based Sensors. The model can predict performance by also placing the specific FPA into an optical
system, evaluates system performance (NEI, NETD, MRTD, and SNR). This model has been used as a tool for
predicting performance of state-of-the-art detector arrays and nanostructure arrays under development. Results of the
analysis can be presented for various targets for each of the focal plane technologies for a variety of missions.
KEYWORDS: 3D modeling, Sensors, Minimum resolvable temperature difference, Bolometers, Performance modeling, Atmospheric modeling, Modulation transfer functions, Image sensors, Signal to noise ratio, Thermal modeling
Presented is a comprehensive, physics-based model for microbolometer detector and sensor performance prediction. The
model combines equations found in the literature and various standard models that generate NETD, MRTD, 3-D noise
statistics and atmosphere characteristics (MODTRAN-based), with a comprehensive microbolometer model and HgCdTe
model developed by the author to provide an end-to-end detector/FPA/sensor analysis and design tool, as well as a
realistic image sequence generation tool. The model characterizes the individual pixel element based on the structure
used, the various layer thicknesses, the electrical and thermal characteristics of the bolometer material and the biasing
and readout circuit, and uses these results to calculate response and noise, NEP and NETD. The NETD, MTF and
MRTD are predicted from the optics, detector and readout. Predicted NETD has been compared and verified with values
found in literature, results from other models, and to uncooled camera measurements. The MRTD prediction has been
verified with camera measurements and with standard industry MRTD model outputs. The model also calculates
atmospheric path radiance and transmittance for horizontal paths based on MODTRAN outputs for the LWIR band at
altitudes from 0 to 10km and ranges from 1 to 50km for assessments of air-to-air engagement SNR's. The model in
matlab utililizes a 3-D noise model to provide accurate realistic imagery used to present realistic sensor images and to
further validate the NETD and MRTD routines.(1) Images at 30Hz and 60Hz have been generated for visual assessment
by the user and have mirrored industry model results and real-time camera images for MRTD's for the temporal noise
case. The model's 3-D noise generation feature allows the prediction of MRTD vs. frequency under any 3-D noise
combination. This model provides an end-to-end performance prediction tool useful in bolometer element design,
readout design and for system level trade studies.
KEYWORDS: Signal to noise ratio, Sensors, Germanium, Infrared sensors, Near infrared, Silicon, Diodes, Black bodies, Staring arrays, Indium gallium arsenide
Low cost IR Sensors are needed for a variety of Military and Commercial Applications. SiGe based IR Focal Plane Arrays offer a low cost alternative for developing near IR sensors that will not require cooling and can operate in the visible and NIR bands. The attractive features of SiGe based IRFPA's will take advantage of Silicon based technology, that promises small feature size and compatibility with the low power silicon CMOS circuits for signal processing.
A feasibility study of an infrared sensor based on SiGe material system and its performance characteristics are presented. Simulations comparing the sensitivity of the SiGe detector with spectral cutoff wavelength of 1.6 micron to other IR Focal Plane arrays are discussed. Measured electrical and optical characteristics of Ge-on-Si photodetectors are also presented.
This model was developed in matlab with I/O links to excel spreadsheets to add realistic and accurate sensor effects to
scene generator or actual sensor/camera images. The model imports scene generator or sensor images, converts these
radiance images into electron maps and digital count maps, and modifies these images in accordance with user-defined
sensor characteristics such as the response map, the detector dark current map, defective pixel maps, and 3-D noise
(temporal and spatial noise). The model provides realistic line-of-sight motion and accurate and dynamic PSF blurring
of the images. The sensor model allows for the import of raw nonuniformities in dark current and photoresponse,
performs a user-defined two-point nonuniformity correction to calculate gain and offset terms and applies these terms to
subsequent scene images. Some of the model's capabilities include the ability to fluctuate or ramp FPA and optics
temperatures, or modify the PSF on a frame-by-frame basis. The model also functions as an FPA/sensor performance
predictor and an FPA data analysis tool as FPA data frames can be input into the 3-D noise evaluation section of the
model. The model was developed to produce realistic infrared images for IR sensors.
This paper reports on a model developed to predict bolometer performance in its environment, where the environment
consists of thermal, optical and electrical components. Two complementary methods were employed to predict
performance. The first solves the heat balance equation for the bolometer in its circuit and its thermal environment with
known values of heat capacitance, thermal conductance, absorptance, temperature coefficient of resistance and the userdefined
bias current (either constant or pulsed). This iteration yields a bolometer temperature rise, and a corresponding
change in resistance and voltage. This is the signal part of the equation. The second method is required to calculate the
total bolometer noise. It uses equations derived from the literature to predict bolometer noise, response, NEP and NETD
from first principles for the four types of noise generated in thermal detectors (thermal fluctuation noise, background
fluctuation noise, johnson noise and 1/f noise). Thermal conductance and heat capacities are calculated using all the
elements of the bolometer structure such as the silicon nitride structure, the VOx coating, and the nichrome electrical
leads. Using a calculation of the full spectral irradiance on the bolometer from the scene and the dewar and a userdefined
bolometer element spectral absorption, the model will accurately assess performance in any environment. The
model also employs a 3-D noise model and provides synthetic images of PSF-blurred bar targets for NETD and MRTD
predictions.
This model was developed to provide a means for comparative assessments of HgCdTe FPA's and sensors operating in
the infrared spectral bands that coincide with the atmospheric windows - (SW1(1.5-1.8μ), SW2(2-2.5μ), MW(3-5μ), and
LW(8-12μ). As a true imaging model it also functions as an assessment tool for single-band imagery and for multi-color
imagery. The HgCdTe model characterizes both n-on-p and p-on-n homojunctions and heterostructures. Diffusion and
depletion dark currents and RoA's are calculated for the three common configurations (mesa heterojunction, planar ionimplanted
or diffused junction, and the vertically integrated photodiode). The model places the specified FPA into an
optical system, evaluates system performance (NEI, NETD, MRTD, and SNR) and creates two-point corrected imagery
complete with 3D noise image effects. This model was exercised here as a predictive tool for performance of state-of-the-
art detector arrays in optical systems in the four spectral bands (atmospheric windows) from the SW to the MW (1.5-
1.8, 2.0-2.5, 3.4-4.2 and 4.5-5.0 um) which are the bands commonly considered for hot target and plume exhaust
detection. Results from the literature and model runs for various target and scene sets show promise for HgCdTe FPA's
and sensors developed for the 2-2.5 μm band for a variety of missions such as threat detection from UAV or satellite
platforms, perimeter defense, and high-altitude intercepts.
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