CCD- and CMOS-Imaging

Visit Mid-Sweden University - November 2006

Prof. Dr. Arno Ruckelshausen Faculty of Engineering and Computer Science

Interdisciplinary Reserach Center Intelligent Sensor Systems (ISYS)

CCD- and CMOS-Imaging

CCD- and CMOS-Imaging

If a picture tells more than 1000 words,

imaging is the language of the future !Albert Theuwissen, DALSA/ The Netherlands and Delft University/Belgium

Imaging

CCD- and CMOS-Imaging

1969

Woodstock Moon landing Invention of the CCD

CCD- and CMOS-Imaging

Overview

CCD Principles

Device Architectures: Frame Transfer and Interline

Special Aspects

CMOS Principles

CCD- and CMOS-Imaging

OverviewOverviewOverview

CCD Principles

Device ArchitecturesDevice ArchitecturesDevice Architectures: Frame Transfer and : Frame Transfer and : Frame Transfer and InterlineInterlineInterline

Special Special Special AspectsAspectsAspects

CMOS CMOS CMOS PrinciplesPrinciplesPrinciples

CCD- and CMOS-Imaging

The Human Eye and the CCD Imager

Human Eye

120 Mpixels2-3 micron pixels< 1 mWperfect qualitycolor: perfectparallel read-out15 images/sec500 Myears

CCD Imager

80 Mpixels2-12 micron pixels1 Wgood qualitycolor: goodserial read-outup to 1.000.000 images/sec25 years

CCD- and CMOS-Imaging

MOS structure

SiO2 (oxide)Poly Si Gate

V

0 Volt 5 Volt

Silicon

CCD- and CMOS-Imaging

CCD

V

C1

0V

C2

0V

C3

5V

C1

0V

C2

0V

CCD- and CMOS-Imaging

V

C1

0V

C2

0V

C3

5V

C1

0V

C2

0V

CCD

CCD- and CMOS-Imaging

Transport

C1 C2 C3 C1 C2 C3 C1

t1

t2

t3

t4

storage separation

transfer

CCD- and CMOS-Imaging

Transport – comparison with water

CCD- and CMOS-Imaging

Surface CCD

0V 0V 10V 0V 0V 10V 0V

Vq

CN

CCVCQ

ox

ox

∆⋅=

=∆⋅=∆

Cox = 0.345 fF/µm2

∆V = 10V

N ≈ 20 000 e-/µm2

Oxide (0.1 µm)

CCD- and CMOS-Imaging

0V 0V 10V 0V 0V 10V 0V

Vq

CN

CCCCC

C

VCQ

eff

oxSiox

Sioxeff

∆⋅=

<+⋅

=

∆⋅=∆

Ceff = 0.15 fF/µm2

∆V(bulk) = 7

N ≈ 6 500 e-/µm2

Buried channel CCD

CCD- and CMOS-Imaging

OverviewOverviewOverview

CCD CCD CCD Principles Principles Principles

Device Architectures: Frame Transfer and Interline

Special Special Special AspectsAspectsAspects

CMOS CMOS CMOS PrinciplesPrinciplesPrinciples

CCD- and CMOS-Imaging

Linear Imager (1D)

Photo diode

Light shield Output

amplifier

outCCD register

CCD- and CMOS-Imaging

Interline Imager: IL-CCD (2D)

out

CCD- and CMOS-Imaging

Interline CCD: Basic operation

CCD- and CMOS-Imaging

Frame Transfer FT-CCD (2D)

out

CCD- and CMOS-Imaging

Frame Transfer CCD: Basic operation

CCD- and CMOS-Imaging

Full Frame CCD (FF-CCD)

CCD- and CMOS-Imaging

Timing diagram

Source: „Solid -State Imaging with Charge-Coupled Devices, A.J.P. Theuwissen, Kluwer 1995

Transport Systems : Four-phase CCD

CCD- and CMOS-Imaging

Example: Floating diffusion amplifier (FDA):

Ø charge packet is transported into the floating diffusion

Ø sensed by an amplifier

Ø reset via a MOS-transistor

Output structure

CCD- and CMOS-Imaging

OverviewOverviewOverview

CCD CCD CCD Principles Principles Principles

Device ArchitecturesDevice ArchitecturesDevice Architectures: Frame Transfer and : Frame Transfer and : Frame Transfer and InterlineInterlineInterline

Special Aspects

CMOS CMOS CMOS PrinciplesPrinciplesPrinciples

CCD- and CMOS-Imaging

Color Imaging: Spectral Sensitivity of the human eye

Source: „Physics of Semiconductor Devices“, S.M.Sze, Wiley 1981

CCD- and CMOS-Imaging

photon

elektron

nn

=η

Quantum Efficiency

λ

Image sensor with colour filters:

RGB-pattern („Bayer Pattern“)

Color and image sensors

CCD- and CMOS-Imaging

3 Chip Camera

CCD- and CMOS-Imaging

Blooming

Reference Picture Bright light spot

Blooming

Source: „Solid-State Imaging with Charge-Coupled Devices, A.J.P. Theuwissen, Kluwer 1995

CCD- and CMOS-Imaging

Antiblooming: Vertical antiblooming

CCD- and CMOS-Imaging

Number of electrons versus light intensity (overview)

Source: „Design and Fabrication of Integrated Image Sensors“, Course of R.I.Hornsy, University of Waterloo

CCD- and CMOS-Imaging

Smear

Reference Picture Bright light spot

Smear

Source: „Solid-State Imaging with Charge-Coupled Devices, A.J.P. Theuwissen, Kluwer 1995

CCD- and CMOS-Imaging

OverviewOverviewOverview

CCD CCD CCD Principles Principles Principles

Device ArchitecturesDevice ArchitecturesDevice Architectures: Frame Transfer and : Frame Transfer and : Frame Transfer and InterlineInterlineInterline

Special Special Special AspectsAspectsAspects

CMOS Principles

CCD- and CMOS-Imaging

System technology

CCD imager

Timing Generator PC

ic1

ic3

Driversic2

ASPic4

ADCic5

DSPic6

CMOS Camera-on-a-Chip

... tomorrow

Yesterday ...

CCD- and CMOS-Imaging

MOS characteristics

CCD- and CMOS-Imaging

Example of a pixel structure: Passive pixel sensor (PPS)

CCD- and CMOS-Imaging

CMOS image sensors: general items

☺ Low Cost ( 2002: K)

☺ System integration

L Complexity

☺ Adressability

☺ Programmable frame rate

☺ Automatic gain control

K Image quality (1999: L)

CCD- and CMOS-Imaging

CMOS-camera „FUGA15“

Example: CMOS imager

CCD- and CMOS-Imaging

Source: IMEC/ Belgium, Internet: www.imec.be, 1998

CMOS APS in 0.7µm technology512 * 512 random addressable pixelspixel pitch 12.5 * 12.5µm²dye size 7.5 * 7.5 mm²non-integrating, with logarithmic response5 MHz pixel rateon chip 8 bit AD converterspectral range 400 - 1 050 nmpixel fill factor 15% packaging 48 pin ceramic with glass cover, plastic in option, B/W & RGB available 5 Volt single power line

FUGA-camera

Example: CMOS imager

CCD- and CMOS-Imaging

Logarithmic response (example)

CCD- and CMOS-Imaging

Windowing and subsampling (every nth pixel)

CCD- and CMOS-Imaging

Windowing/ROI:(Region of Interest)

Camera-controlled goalkeeper

CCD- and CMOS-Imaging