Optical Basics MEMS - RIT - People · Optical Basics - MEMS Page 1 ... 436 nm 0.5 0.0 Wavelength...

© December 20, 2016 Dr. Lynn Fuller, Professor

Optical Basics - MEMS

Rochester Institute of Technology

Microelectronic Engineering

ROCHESTER INSTITUTE OF TECHNOLOGYMICROELECTRONIC ENGINEERING

Optical Basics _MEMS

Dr. Lynn FullerWebpage: http://people.rit.edu/lffeee

Microelectronic EngineeringRochester Institute of Technology

82 Lomb Memorial DriveRochester, NY 14623-5604

Email: [email protected] Webpage: http://www.rit.edu/microelectronic/

12-20-2016 Optical_Basics_MEMS.ppt

http://people.rit.edu/lffeee

mailto:[email protected]

http://www.rit.edu/microelectronic/





OUTLINE

Light Sources

Light Detectors

Optic Components

Mirrors

Light Emissive Devices

Light Modulators

References

Homework





SPECTRICAL DISTRIBUTION OF SOLAR RADIANT POWER

From: Micromachined Transducers, Gregory T.A. Kovacs





BLACK BODY, AM0 AND AM1.5

From: Solar Cells, Martin A. Green, Prentice Hall





BLACK BODY RADIATION

From: Solar Cells, Martin A. Green, Prentice HallFrom: Micromachined Transducers, Gregory T.A. Kovacs

Wien’s Displacement Law

lpeak = 2898/T (µm)

lpeak = 2898 µm / T

h = 6.6262E-34 J s = 4.1361E-15 eV s

l= c/n k=1.38e-23 J/K

Wl = radiant flux

e(l) = emissivity (dimensionless, e=1 for black body)





PLANCK’S LAW

I is spectral radiance (w/m2/…….)

Wl is radiant flux (w/m2)

h = 6.6262E-34 J s = 4.1361E-15 eV s

l= wavelength = c/n

n = frequency

c = 2.998E8 m/s

k =1.38e-23 J/K

e(l) = emissivity (dimensionless, e=1 for black body)

Planck’s Law: (Spectral Radiance) Power per unit time radiated per unit area of emitting surface in the normal direction per unit solid angle per unit frequency.

This equation is used to approximate emissions from black body sources.





HOT FILIMENT “BLACK BODY” LIGHT SOURCES

600 µm

100 µm

Dave BorkholderSenior project 1993

MOVIE





EMISSION SPECTRA OF THE Hg VAPOR BULB

300 400 500 600 700

1.0i-line, 365 nm

g-line, 436 nm

0.5

0.0

Wavelength (nm)

h f

e





LED IV CHARACTERISTICS

VD

ID

2.0

LED

-10.0

Light

Flat

n

p

Light Emitting Diode -LED

- Va +





LIGHT EMITTING DIODES (LEDs)

P-side N-side

Space

charge

Layer

LightLight

Hole concentration vs distnace

xx

Electron concentration vs distance

In the forward biased diode current flows and as holes recombine on the n-side or electrons recombine on the p-side, energy is given off as light, with wavelength appropriate for the energy gap for that material. l = h c / E

h = Plank’s constantc = speed of light





LEDs

SFH4110

SEP8736

SEP8736





RIT’S FIRST LED

GaP wafers with n-type epilayer, add

gold metal, dice and wire bond to RIT

thick film ceramic package.





RELATIVE LUMINOSITY VS WAVELENGTH

Human eye perceives 550nm (green-yellow) as the brightest, the relative luminosity of other colors is give above





PHOTODIODE

B -

P+ Ionized Immobile Phosphrous donor atom

Ionized Immobile Boron acceptor atom

Phosphrous donor atom and electronP+

-

B-

+Boron acceptor atom and hole

n-type

p-type

B - P+

B -B -

B -B -

P+ P+P+P+

P+

P+

P+

-

B-

+

eB -B -

P+

-P+

-P+

-

B-

+

-+

-+

I

electron

and hole

pair

-+

-+

space charge layer





CHARGE GENERATION IN SEMICONDUCTORS

E = hn = hc / l

What wavelengths will not

generate e-h pairs in silicon.

Thus silicon is transparent or

light of this wavelength or

longer is not adsorbed?

From: Micromachined Transducers,

Gregory T.A. Kovacs

Material Bandgap

eV @ 300°K

lmax

(um)

GaN 3.360 0.369

ZnO 3.350 0.370

SiC 2.996 0.414

CdS 2.420 0.512

GaP 2.260 0.549

CdSe 1.700 0.729

GaAs 1.420 0.873

InP 1.350 0.919

Si 1.120 1.107

Ge 0.660 1.879

PbS 0.410 3.024

PbTe 0.310 4.000

InSb 0.170 7.294





WIDTH OF SPACE CHARGE LAYER

Width of space charge

layer depends on the

doping on both sides

and the applied reverse

bias voltage and

temperature.





CHARGE GENERATION vs WAVELENGTH

II

n-type

p-type

e

l1 l3 l4l2

E = hn = hc / l

h = 6.625 e-34 j/s

= (6.625 e-34/1.6e-19) eV/s

E = 1.55 eV (red)

E = 2.50 eV (green)

E = 4.14 eV (blue) B - P+

B -B -

B -B -

P+ P+P+P+

P+

P+

P+

-

B-

+

B -B -

P+

-P+

-P+

-

B-

+

-+-

+-

+

To generate e-h pair in silicon we need E > Egap

E > 1.12 eV





ADSORPTION VERSUS DISTANCE

I

V

n

p

IV

I

+

V

-

More Light

No Light

Most Light

f(x) = f(0) exp-a x

Find % adsorbed for Green light

at x=5 µm and Red light at 5 µm

1.00E-06

1.00E-05

1.00E-04

1.00E-03

1.00E-02

1.00E-01

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

1.00E+06

250 450 650 850 1050 1250 1450

Adsorption Coefficient vs Wavelength

Wavelength (nm)

Adso

rpti

on C

oef

fici

ent,

a (

1/c

m) For Silicon





PN JUNCTION DESIGN FOR PHOTO DIODE

0µm 1µm 2µm 3µm 4µm

67%

100%

@850nm

@550nm

1017

1015

Space Charge Layer

60%





PIN, AVALANCE PHOTODIODES (APD)

n-sidep-side

IntrinsicP I N

W2W1 0 0

PIN and Avalance photo diodes (APD) are made with an intrinsic (almost zero doping) layer between the N and P layers. The depletion layer is increased by the width of the Intrinsic layer. Avalance diodes are the same structure but used with large reverse bias (>100 volts) that creates large electric field in the space charge layer that can accelerate the electrons to velocities high enough to cause ionizing collisions giving a multiplication of carriers. Each photon can generate hundreds of electron hole pairs.





PIN, AVALANCE PHOTODIODES (APD)

www.silicon-sensor.com





Photo Multiplier Tube (low work Function)

-2000 V

-3000 V

-4000 V

hv-1000 V

R

Vout

PHOTOMULTIPLIER





CHARGE COLLECTION IN MOS STRUCTURES

e

-+

-+

electron

and hole

pair

-+

-+

depletion region

-+

-- -

p-type

+ V

B -

B -

B -

B -

l1 l3 l4l2

thin poly gate

E = hn = hc / l

h = 6.625 e-34 j/s

= (6.625 e-34/1.6e-19) eV/s

E = 1.55 eV (red)

E = 2.50 eV (green)

E = 4.14 eV (blue)





TRANSMISSION PROPERTIES OF OPTICAL GLASS

200 400300250 350

Wavelength (nm)

Green Soda Lime Glass

60 mils

White Crown Glass

60 mils

Borosilicate Glass

60 mils

Tra

nsm

issi

on

, %

20

40

60

100

80Quartz, 90 mil





THERMOPILE SENSOR

www.heimannsensor.com

http://www.heimannsensor.com/





RIT THERMOPILE SENSOR

Output voltage vs Input power for wafer 4

-50

0

50

100

150

200

250

300

350

0 0.1 0.2 0.3 0.4 0.5

Input power(mW)

Ou

tpu

t V

olt

ag

e(u

V)

Die 3 ,

R= 12.2

Kohms

Die 5,

R=

14.32

kohmsDie 6 ,

R=

14.32

kohmsDie 7,

R= 15

Kohms

Usha Kuppuswamy, 2005





FIBER OPTIC COMPONENTS





LASER AND FRESNEL LENS





OPTICAL SYSTEM

Fresnel Lens





HINDGE





SELF ASSEMBLY





ELECTROSTATIC COMB DRIVE

Movies at www.sandia.gov

http://www.sandia.gov/





ELECTROSTATIC COMB DRIVE MIRROR

Movie





ELECTROSTATIC MIRROR

www.memsoptical.com

http://www.memsoptical.com/





MIRRORS

MOEMs - Micro Optical Electro Mechanical Systems

Lucent Technologies –

Lambda router, 256 mirror fiber optic multiplexer





TORSION - MIRROR

Substrate

poly 1poly 0

Movable mirror

Inflectionpoint

Micro-mirror Perspective View

Torsion Hinge





POLYIMIDE ON HEATER

Jeremiah Hebding

Movie





THERMALLY ACTUATED MEMS MICRO MIRROR





DIGITAL MIRROR LIGHT PROJECTION SYSTEM





TORSIONAL MIRRORS





TI MICROMIRROR PROJECTOR





TEXAS INSTRUMENTS DIGITAL PROJECTION PRODUCTS

www.TI.com

Movie

http://www.ti.com/





DXtreme PRO1





FIELD EMISSION TIPS FORFLAT PANNEL DISPLAYS

1 µm

Alex Raub, 1995, now atNational SemiconductorSanta Clara, CA





FIELD EMISSION FLAT PANNEL DISPLAYS

Substrate

Insulator

Vacuum Chamber

TransparentSi

O2 Window

EmitterControl Gate

Low Voltage Phosphor

Seal/Plug

Integrated Phosphor

Field Emission

Device

.900

.800

.700

.600

.500

.400

.300

.200

.100

000 .100 .200 .300 .400 .500 .600 .700 .800

GREEN

BLUISHGREEN

BLUE

BLUE

GREEN

PINK

PURPLISHRED

RED

REDDISHPURPLE

YELLOWISH

BLUEGREENISH

GREEN

Color Chart of AVT PhoshorsMicro-encapsulated Chamber





REFLECTIVE MECHANICAL LIGHT MODULATOR





RIT LIGHT MODULATOR - SENIOR PROJECT

Sushil Shakya





REFERENCES

1. Micro Spectro Photometer by Marion Jess, Carl Duisberg

Gesellschaft e.V., Fachhochschule Koln, Germany , August 1996.

2. Fundamentals of Microfabrication, Marc Madou, CRC Press, LLC,

1997.

3. Scientific Measurement Systems, Inc., 2527 Foresight Circle, Grand

Junction, CO 81505-1007.

4. Micromachined Transducers, Gregory T. A. Kovacs, McGraw-Hill,

1998

5. Solar Cells, Martin A. Green, Prentice-Hall





HOMEWORK – OPTICAL BASICS FOR MEMS

1. If the human body is thought of as a black body light source.

What types of optical detector will be able to sense a human

by sensing its IR emission? Explain.

2. Look up the Texas Instruments Digital Light Projector

products. What is the cost of a developer kit for some of

their projection products.

3. Visit the following web sites and discuss one product of

interest for each. www.silicon-sensor.com

www.heimannsensor.com

www.oceanoptics.com

www.memsoptical.com

http://www.silicon-sensor.com/

http://www.heimannsensor.com/

http://www.oceanoptics.com/

http://www.memsoptical.com/

Optical Basics MEMS - RIT - People · Optical Basics - MEMS Page 1 ... 436 nm 0.5 0.0 Wavelength...

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