James Beletic's presentation

High Performance Imaging Sensors
for Astronomy & Civil Space
18 March 2010
James W. Beletic

Teledyne – NASA’s s and ESA’s s Partner in Astronomy
HST WISE JWST
J-MAPS
NICMOS, WFC3, ACS Repair
Bands 1 & 2
NIRCam, NIRSpec, FGS
1 st CMOS for astronomy
Rosetta
Mars
Reconnaissance
Orbiter
Deep Impact
& EPOXI
New Horizons
Lander (çiva) CRISM (Vis & IR) IR spectrograph IR spectrograph
JDEM
Joint Dark Energy Mission
NASA and U.S. DOE
(Department of Energy)

Hubble Space Telescope

Hubble Space Telescope
Wide Field Camera 3
H1-R
Quantum Efficiency = 85-90%
Dark current (145K) = 0.02 e-/pix/sec
Readout noise = 25 e- (single CDS)
GSFC DCL Measurement
• 1024×1024 pixels, 18.5 micron pitch
• Substrate-removed 1.7 μm HgCdTe arrays
• Nearly 30x increase in HST discovery efficiency

James Webb Space Telescope (JWST)

JWST - James Webb Space Telescope
15 Teledyne 2K×2K infrared arrays on board (~63 million pixels)
6.5m mirror
Earth
sunshield
FGS
(Fine Guidance Sensors)
• International collaboration
• 6.5 meter primary mirror and
tennis court size sunshield
• 2015 launch on Ariane 5 rocket
• L2 orbit (1 million miles from Earth)
JWST will find the “first light”
objects after the Big Bang, and
will study how galaxies, stars
and planetary systems form
NIRSpec
(Near Infrared Spectrograph)
SIDECAR ASIC
Focal Plane Electronics
15 ASICs will operate in JWST
One ASIC per H2RG array
NIRCam
(Near Infrared Camera)
3 individual MWIR 2Kx2K
• Acquisition and guiding
• Images guide stars for telescope
stabilization
• Canadian Space Agency
1x2 mosaic of MWIR 2Kx2K
• Spectrograph
• Measures chemical composition,
temperature and velocity
• European Space Agency / NASA
All Sensors Delivered
ASIC deliveries to be completed in June 2010
Two 2x2 mosaics
of SWIR 2Kx2K
Two individual
MWIR 2Kx2K
• Wide field imager
• Studies morphology of objects
and structure of the universe
• U. Arizona / Lockheed Martin
6

NASA’s s Partner for Earth Science
LDCM
TIRS
NPOESS
CrIS
CHANDRAYAAN-1
GOES-R
ABI
(LWIR)
(SWIR)
GLORY
Moon Mineralogy Mapper
(Vis-IR)
EO-1
AURA
Tropospheric Emission Spectrometer
IR FT Spectrometer
OCO-R
Orbiting Carbon
Observatory
(Vis & IR)
Visible to 16.5 microns
LEISA
Atmospheric
Corrector
(IR arrays)
Working on development for several future missions
HyspIRI (Vis-SWIR and Thermal IR), ACE, OCO Re-flight, AVIRISng, PRISM, Himawari

Moon Mineralogy Mapper
Discovers Water on the Moon
Focal Plane Assembly
Sensor Chip Assembly
Instrument at JPL before
shipment to India
Completion of Chandrayaan-1 spacecraft integration
Moon Mineralogy Mapper is white square at end of arrow
Chandrayaan-1 in the
Polar Satellite Launch Vehicle
Launch from Satish
Dhawan Space Centre
Moon Mineralogy Mapper resolves visible and infrared
to 10 nm spectral resolution, 70 m spatial resolution
100 km altitude lunar orbit

Orbiting Carbon Observatory (OCO)
Teledyne Focal Plane Arrays
• Three flight FPAs:
• O 2 A band at 0.758-0.772 µm
• weak CO 2 band at 1.594 -1.619 µm
• strong CO 2 band at 2.042-2.082 µm
• Hawaii-1RG readout is used for both HyViSI and SWIR
FPAs with same mechanical and nearly same electrical
interface for all three OCO spectrometers.
• Re-Flight may use substrate-removed HgCdTe for all
three bands
9

Leading Supplier of Infrared Arrays To Ground-based Astronomy
• Shipped over 45 science grade 2048×2048 pixel infrared arrays for
facility class instruments to the major ground based observatories
• Eight 2 x2 mosaics of H2 / H2RGs at ground based telescopes
Magellan Telescopes, OCIW - Chile
Calar Alto Observatory – Spain
ESO VLT 8.2-m telescope
ESO Very Large Telescope (VLT) Facility - Chile
10

The Technologies of High Performance Imagers
11

An electron-volt
(eV)
is extremely small
15 H2RG
2K×2K arrays
63 million pixels
1 eV = 1.6 • 10 -19 J (J = joule)
1 J = N • m = kg • m • sec -2 •m
1 kg raised 1 meter = 9.8 J = 6.1 • 10 19 eV
• The energy of a photon is VERY small
– Energy of SWIR (2.5 μm) photon is 0.5 eV
• In 5 years, JWST will take ~1 million images
– 1000 sec exp., 15 H2RGs, 90% duty cycle
– Photons / H2RG image ≈ 3.6 × 10 10 photons
• 5% pixels at at 85% full well
• 10% " at at 40% full well
• 10% " at at 10% full well
• 75% " at at 1% full well
Full well
85,000 e-
– Total # SWIR photons detected ≈ 3.6 × 10 16
– Total energy detected ≈ 1.8 × 10 16 eV
• Drop peanut M&M ® candy (~2g) from
height of 15 cm (~6 inches)
– Potential energy ≈ 1.8 x 10 16 eV
15 cm peanut M&M ® drop is
equal to the energy detected
during 5 year operation of the
James Webb Space Telescope!

Hybrid CMOS Infrared Imaging Sensors
Three Key Technologies
1. Growth and processing of the
HgCdTe detector layer
2. Design and fabrication of the
CMOS readout integrated circuit
(ROIC)
3. Hybridization of the detector layer
to the CMOS ROIC
15

6 Steps of CMOS-based Optical / IR Photon Detection
Anti-reflection coating
Substrate removal
Detector Materials
HgCdTe, Si
1. Light into detector
2. Charge Generation
Quantum
Efficiency
Electric Fields in detector
collect electrical charge
p-n junction
Source follower
3. Charge Collection
4. Charge-to-Voltage
Conversion
Point
Spread
Function
Sensitvity
HYBRID SENSOR
CHIP ASSEMBLY (SCA)
Random access
or full frame read
5. Signal Transfer
SIDECAR
ASIC
6. Digitization
16

Crystals are excellent detectors of light
• Simple model of atom
– Protons (+) and neutrons in the nucleus
with electrons orbiting
Silicon crystal lattice
• Electrons are trapped in the crystal lattice
– by electric field of protons
• Light energy can free an electron from the
grip of the protons, allowing the electron to
roam about the crystal
– creates an “electron-hole” pair.
• The photocharge can be collected and
amplified, so that light is detected
• The light energy required to free an electron
depends on the material.

II III IV V VI
Detector Families
Si - IV semiconductor
HgCdTe - II-VI semiconductor
InGaAs & InSb - III-V semiconductors

Tunable Wavelength: Unique property of HgCdTe
Hg 1-x Cd x Te Modify ratio of Mercury and Cadmium to “tune” the bandgap energy
2
( 1−
x)
E g = −0.302
+ 1.93x
− 0.81x
+ 0.832 x + 5.35 × 10 T 2
G. L. Hansen, J. L. Schmidt, T. N. Casselman, J. Appl. Phys. 53(10), 1982, p. 7099
3
−4
20

Absorption Depth of Photons in HgCdTe
Rule of Thumb
Thickness of HgCdTe layer
needs to be about equal
to the cutoff wavelength
Absorption Depth
Thickness of detector material that absorbs 63.2% of the radiation
1/e of the energy is absorbed
1 absorption depth(s) 63.2% of light absorbed
2 86.5%
3 95.0%
4 98.2%
For high QE, thickness of detector material should be ≥ 3 absorption depths
21

Molecular Beam Epitaxy (MBE) Growth of HgCdTe
RIBER 3-in MBE Systems
3 inch diameter platen
allows growth on one
6x6 cm substrate
RIBER 10-in MBE 49 System
10 inch diameter
platen allows
simultaneous growth
on four 6x6 cm
substrates
More than 7500 HgCdTe
wafers grown to date
22

HgCdTe Cutoff Wavelength
Atmospheric Transmission
Wavelength (microns)
“Standard” Ground-based astronomy
cutoff wavelengths
Near infrared (NIR)
1.75 µm J,H
Short-wave infrared (SWIR) 2.5 µm J,H,K
Mid-wave infrared (MWIR) 5.3 µm J,H,K,L,M
23

6 Steps of CMOS-based Optical / IR Photon Detection
Anti-reflection coating
Substrate removal
Detector Materials
HgCdTe, Si
1. Light into detector
2. Charge Generation
Quantum
Efficiency
HYBRID SENSOR
CHIP ASSEMBLY (SCA)
Electric Fields in detector
collect electrical charge
p-n junction
Source follower
3. Charge Collection
4. Charge-to-Voltage
Conversion
Point
Spread
Function
Sensitvity
Random access
or full frame read
5. Signal Transfer
SIDECAR ASIC
SIDECAR ASIC
6. Digitization
24

HgCdTe hybrid FPA cross-section (substrate removed)
Incident
Photons
Bulk n-type HgCdTe
Anti-reflection
coating
implanted p-type HgCdTe
(collect holes)
indium bump
silicon multiplexer
epoxy
MOSFET input
Output
Signal
25

Hybrid Imager Architecture
HgCdTe light
detecting material
ROIC
junction
Indium
bump
V dd
amp drain voltage
Reset
junction
Indium
bump
junction
Indium
bump
V reset
reset voltage
Column
bus
enable
Bus to read out amplifier signal
MOSFET = metal oxide semiconductor field effect transistor
H4RG-10
4096x4096 pixels
10 micron pixel pitch
HyViSI silicon PIN
Mature interconnect technique:
• Over 16,000,000 indium
bumps per Sensor Chip
Assembly (SCA)
demonstrated
• >99.9% interconnect yield
Example of indium bumps
Human Hair

Cosmic Rays and Substrate Removal
• Cosmic ray events produce clouds of detected signal due to particle-induced flashes
of infrared light in the CdZnTe substrate; removal of the substrate eliminates the effect
2.5um cutoff, substrate on 1.7um cutoff, substrate on 1.7um cutoff, substrate off
Substrate Removal Positive Attributes
1. Higher QE in the near infrared
2. Visible light response
3. Eliminates cosmic ray fluorescence
4. Eliminates CTE mismatch with silicon ROIC
Images courtesy of Roger Smith
27

Quantum Efficiency of substrate-removed HgCdTe
Quantum Efficiency of 2.3 micron HgCdTe
28

Example Anti-reflection coatings for HgCdTe
100%
Transmission into the HgCdTe Layer (%)
Transmission (%)
90%
80%
70%
60%
50%
40%
30%
20%
10%
Single Layer (WFC3)
Double Layer
Three Layer (NIRCAM SWIR)
0%
400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600
Wavelength (nm)
29

Dark Current
Undesirable byproduct of light detecting materials
Colder Temp
Fraction of lattice
Warmer
Temp
E g
These vibrations have
enough energy to pop
electron out of the valence
band of the crystal lattice
Energy of vibration
• The vibration of particles (includes crystal lattice phonons, electrons and holes) has
energies described by the Maxwell-Boltzmann distribution. Above absolute zero, some
vibration energies may be larger than the bandgap energy, and will cause electron
transitions from valence to conduction band.
• Need to cool detectors to limit the flow of electrons due to temperature, i.e. the dark
current that exists in the absence of light.
• The smaller the bandgap, the colder the required temperature to limit dark current
below other noise sources (e.g. readout noise)

Dark Current of MBE HgCdTe
Dark
Current
10 8
10 7
10 6
10 5
10 4
Typical InSb
Dark Current
~9
~5 ~2.5
Electrons
per pixel
per sec
10 3
10 2
10
18 micron
square
1
pixel 10 -1
~1.7
10 -2
10 -3
10 -4 30 50 70 90 110 130 150 170 190 210 230
Temperature (K)
HgCdTe cutoff wavelength (microns)
31

6 Steps of CMOS-based Optical / IR Photon Detection
Anti-reflection coating
Substrate removal
Detector Materials
HgCdTe, Si
1. Light into detector
2. Charge Generation
Quantum
Efficiency
HYBRID SENSOR
CHIP ASSEMBLY (SCA)
Electric Fields in detector
collect electrical charge
p-n junction
Source follower
3. Charge Collection
4. Charge-to-Voltage
Conversion
Point
Spread
Function
Sensitvity
Random access
or full frame read
5. Signal Transfer
SIDECAR ASIC
SIDECAR ASIC
6. Digitization
32

MOSFET Principles
MOSFET = metal oxide semiconductor field effect transistor
Turn on the MOSFET and
current flows from source to
drain
Top view
Source
Gate
Drain
Add charge to gate & the
current flow changes since the
effect of the field of the charge
will reduce the current
Side view
Source
Gate
current
Drain
Metal
Oxide
Semiconductor
Fluctuations in current flow produce “readout noise”
Fluctuations in reset level on gate produces “reset noise”

IR multiplexer pixel architecture
V dd
amp drain voltage
Photovoltaic
Detector
Detector
Substrate
Output

IR multiplexer pixel architecture
Reset
V reset
reset voltage
V dd
amp drain voltage
“Clock” (green)
“Bias voltage” (purple)
Photovoltaic
Detector
Detector
Substrate
Output

IR multiplexer pixel architecture
V dd
amp drain voltage
V reset
reset voltage
Enable
“Clock” (green)
Reset
“Bias voltage” (purple)
Photovoltaic
Detector
Detector
Substrate
Output

General Architecture of CMOS-Based Image Sensors
Control
&
Timing
Logic
(optional)
Vertical Scanner
for Row Selection
Pixel Array
Bias
Generation
& DACs
(optional)
A/D conversion
(optional)
Digital
Output
Horizontal Scanner
/ Column Buffers
Analog
Amplification
Analog
Output

Reduction of noise from multiple samples
Non-destructive readout enables reduction of noise from multiple samples
H2RG array
2.5 micron cutoff
Temperature = 77K
Measured
Simple Theory (no 1/f noise)
CDS = correlated double sample
38

Pixel Amplifier Options
39

High Performance Hybrid CMOS Arrays
High Quality MBE HgCdTe + High Performance CMOS Design + Large Area Hybridization
High Quality
Detectors
High Quantum Efficiency
High Performance Amplifiers
Low Dark Current
Imaging System on Chip Architecture
High Performance Readout Circuits

HyViSI TM – Hybrid Visible Silicon Imager
Focal plane array performance independently verified by:
• Rochester Institute of Technology
• European Southern Observatory
• US Naval Observatory & Goddard Space Flight Center
Readout noise, at 100 kHz pixel rate
• 7 e- single CDS, with reduction by multiple sampling
Pixel operability > 99.99%
41

HyViSI Array Formats
Ground-based Astronomy (Rochester Institute of Technology)
Mars Reconnaissance
Orbiter (MRO)
Crab Nebula (M1)
NGC2683 Spiral Galaxy
Hercules Cluster (M13)
TCM 6604A
640×480 pixels
27 µm pitch
CTIA
1K×1K H1RG-18
2K×2K H2RG-18
4K×4K H4RG-10
J-MAPS
Astrometry
Mission
4K×4K
H4RG-10
Mosaic of 4 arrays
TEC Package by Judson
42

HAWAII-2RG 2048×2048 pixels
HAWAII-2RG (H2RG)
• 2048×2048 pixels, 18 micron pitch
• 1, 2, 4, 32 ports
• “R” = reference pixels (4 rows/cols at edge)
• “G” = guide window
• Low power:

The SIDECAR ASIC – Focal Plane Electronics on a Chip
Replace this
with this!
1% volume
1% power
1% hassle
SIDECAR: System for Image Digitization, Enhancement, Control And Retrieval
44

SIDECAR ASIC – Focal Plane Electronics on a Chip
SIDECAR ASIC
Ground-based package
Hubble Space Telescope
SIDECAR ASIC package
(for ACS Repair*)
SIDECAR ASIC
• 36 analog input channels
• 36 16-bit ADCs: up to 500 kHz
• 36 12-bit ADCs: up to 10 MHz
• 20 output bias channels
• 32 digital I/O channels
• Microcontroller (low power)
• LVDS or CMOS interface
• Low power:
•

Hubble Space Telescope
Advanced Camera for Surveys Repair
• SIDECAR ASIC used to operate the CCD
sensors
• New package developed
46

Spaceflight packaging: JWST Fine Guidance Sensor
• Package for H2RG 2048x2048
pixel array
• TRL-6 spaceflight qualified
• Interfaces directly to the
SIDECAR ASIC
• Robust, versatile package
• Thermally isolated FPA
can be stabilized to 1 mK
when cold finger
fluctuates several deg K
47

SIDECAR ASIC & large mosaic focal plane arrays
2×2 5×7
H2RG 2K×2K
Mechanical Prototype
4×4
H2RG
4x4 Mosaic
for Space Mission
48

Teledyne – Your Imaging Partner for Astronomy & Civil Space
State-of-the-art & high TRL
• CMOS Design
• Detector Materials
• Packaging
• Electronics
• Systems Engineering
Chart 49
Packaging
Electronics
Soft x-ray UV Vis Infrared
0.4 0.7 0.9 16
10 -4 10 -2
HgCdTe
μm
Substrate-removed
Silicon 1.1
CMOS Design Expertise
• Pixel amplifiers – lowest noise to highest flux
• High level of pixel functionality (LADAR, event driven)
• Large 2-D arrays, pushbroom, redundant pixel design
• Hybrids made with HgCdTe, Si, or InGaAs
• Monolithic CMOS
• Analog-to-digital converters
• Imaging system on a chip
• Specialized ASICs
• Radiation hard
• Very low power

Teledyne
Enabling humankind to understand the Universe and our place in it