Solid state lighting, GaN LEDs and lasers

Solid state lighting August 18, 2008
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Solid state lighting,
GaN LEDs and lasers
by Gerhard Fasol PhD
Eurotechnology Japan K. K.
www.eurotechnology.com

Tokyo, August 18, 2008 (Version 11)
©1996-2008 Eurotechnology Japan K. K. All Rights Reserved

©1996-2008 Eurotechnology Japan K. K. 1 www.eurotechnology.com

About the Author of this report�
  Gerhard Fasol is President and Chief Executive Officer of Eurotechnology
Japan KK, a boutique consultancy firm for leaders that he founded in
1996 in Tokyo. Eurotechnology Japan KK advises several of the world’s
largest blue-chip corporations, financial institutions, the Government of
Finland and the European Union on strategy and mergers and
acquisitions. Fasol has been working with Japan’s high-tech sector since
1984. He was manager of one of Hitachi’s research-and-development
labs, and was Associate Professor of the NTT Telecommunications Chair
at Tokyo University.
  Regarding the field of this report, Fasol is the co-author, with key
inventor Shuji Nakamura, of The blue laser diode: The complete story
(2nd ed, Springer-Verlag, October 2000). As well, he has worked for
about 12 years in compound-semiconductor research. He has briefed
the President of Germany, Horst Koehler, and many other global leaders
about Japan’s technology sector. In August 1995, Fasol briefed US
Senator Jeff Bingaman about gallium-nitride light-emitting diodes.
Senator Bingaman’s bill for energy-efficient lighting is mentioned in this
report.
  Fasol graduated with a PhD in Semiconductor Physics from Cambridge
University and Trinity College, Cambridge


Executive Summary�

  The global lighting industry is about to change with the emergence of solid state lighting.
This revolution is:
➔  motivated by the resulting energy savings and reduction of environmental impact
➔  Enabled by the invention of GaN and OLED technology
➔  And accelerated by politics and government (“Ban the Bulb” legislation)
  Today’s size and impact of the lighting industry:
➔  US$100bn for lighting fixtures (of which US$30bn is for lamps).
➔  A total of 15bn installed screw-based light sockets (4bn in the US; 3.6bn in the EU).
➔  US$230bn for electricity + US$50bn for kerosene in the developing world.
➔  Energy-efficient lighting could save US$67bn (100 nuclear-power plants), 600m tonnes of CO2 emission or more and
10,000kg of mercury emission.
  Ban the bulb - Politics accelerates move to energy-efficient lighting:
➔  The California Lighting Efficiency and Toxics Reduction Act (signed by Governor Arnold Schwarzenegger on 12 October
2007).
➔  Senator Jeff Bingaman: “Energy Efficient Lighting for a Brighter Tomorrow Act”.
➔  Well positioned companies (eg, Philips) push for energy-efficient lighting, GE closes its incandescent light-bulb factories.
  Gallium-nitride LED-based solid-state lighting on the way to replace bulbs and tubes:
➔  Can cut the lighting electricity bill by 90%.
➔  LEDs have 50,000 hours lifetime compared to 1,000 hours for incandescent bulbs.
➔  Moore’s law for semiconductors: progress is faster-than-expected.
➔  GaN Light Emitting Diodes (LEDs) and lasers were developed by Shuji Nakamura at Nichia Chemical Industries (located in
Anan, Tokushima-ken, Japan) based on InGaN/AlGaN. The first GaN light emitter was demonstrated by Jack Pankove in the
1970s, and Isamu Akasaki (Matsushita, Univ of Nagoya and Meijo Univ) developed many inventions which enabled Shuji
Nakamura’s first commercialization. Largely invented in Japan, Asia-Pacific companies at important positions today in the
GaN field.



Agenda�
  Executive Summary
  The solid state lighting revolution
➔  Today’s lighting industry
➔  Energy consumption, efﬁciency and environmental impact
➔  Government action, legislation, “Ban the bulb”
➔  Developing countries
  Physics and technology
➔  GaN devices: the three key steps for the breakthrough
➔  White LEDs
➔  Lasers
➔  Why did Shuji Nakamura at Nichia succeed where many much larger corporations failed?
  Markets for GaN LEDs
➔  Trafﬁc signals, street lights, displays and signage, architectural, automotive, backlights, general lighting
  Markets for GaN Lasers
  Patent issues and the “Club of Five”
  The emerging new industry structure
➔  Nichia
➔  Frontline LED makers
➔  Equipment makers and supplies
  Trends and projections
  Summary



The solid state lighting revolution


The solid state lighting revolution is about to disrupt
the global lighting industry
What drives the solid state lighting revolution?�
  Enabled by technology
➔  The solid state lighting revolution is only possible because of the
discovery of GaN LEDs and OLEDs in the 1990s
  Driven by economics and environmental considerations
➔  Today’s lighting (incandescent bulbs and ﬂuorescent tubes) wastes
energy, creates more greenhouse gases than necessary, and releases
harmful poisons (mercury, lead) into the environment
➔  2 billion people have no electricity. They use kerosene for lighting, and
they need to pay 5000 times more to get the same amount of light as
they would pay would they use GaN LEDs
  Accelerated by politics and government
➔  All major countries have legislation in place or on the way to enforce
energy efﬁcient lighting. It is very likely that incandescent light bulbs
are gone within a few years



Dramatic changes coming for today’s
established lighting industry



General Lighting
“Ban the bulb”
Political and Government actions



Developing countries:

the poorest get the worst deal today



Physics and Technology



Why are blue and white GaN LEDs important?�

  Some years ago the active elements in radios and TV-sets were
vacuum tubes. Many years ago these vacuum tubes have been
replaced first by discrete transistors and now by integrated circuits
(ICs).
  Still today, the lighting industry is dominated by glass bulbs and glass
tubes (fluorescent tubes), which despite gradual improvements are
essentially a 100 year old technology with many disadvantages (short
lifetime, bulky and breakable, difficult to recycle, causing environmental
damage, inefficient: most energy input is converted into heat not
desired light, etc)
  GaN based blue, green, white LEDs for the first time allow to replace
light bulbs and fluorescent tubes with semiconductors
  GaN LEDs have started to replace light bulbs and fluorescent tubes
starting with high-value applications (e.g. traffic lights, specialty
lighting, medical applications)



Why are blue lasers important?�

 Blue (violet) GaN based semiconductor
lasers allow to store information with
approx. 4 times higher density and
therefore are the basis for the next
generation DVDs
 Blue (violet) GaN based lasers have
many other applications in medicine,
printing, copying machines and other
areas


Who invented GaN blue LEDs and lasers? Three people:�
  Jacques (Jack) Pankove (1970s at RCA Laboratories, now at
the University of Colorado and Astralux Inc.) found that
Gallium Nitride (GaN) can emit blue light. Jack Pankove’s
memories of his early work can be found here:
➔  http://nsr.mij.mrs.org/2/19/text.html#section1

  Professor Isamu Akasaki (1980s & 1990s initially at
Matsushita Electrical Industries, then at Nagoya University and
now at Meijo University) in patient and systematic research
work in cooperation with Hiroshi Amano and others over many
years developed methods to deposit device quality GaN films,
developed and demonstrated p-type and n-type doping and
developed GaN based light emitting diodes
  Shuji Nakamura (1990s at Nichia Chemical Industries, and now
at University of Santa Barbara) invented a long list of
technologies and processes necessary for commercial
application, and developed GaN LEDs and Lasers to the point
of commercial products. His most important discovery is the
“two-flow MOCVD process” to grow GaN films.



Light spectrum of an LED, a light bulb and a laser�
  Light bulb: tungsten filament heated to about 3000 C emits “black body” radiation over a broad spectrum.
Most emission is invisible infrared heat radition. The efficiency is low, because most input energy is
converted into heat, not into light.
  LED: Light is emitted by the transition of electrons between energy levels, and therefore within a relatively
narrow range of wavelenghts
  Laser: the emission of a laser is determined by the resonance of an “optical amplifier” and an optical
cavity. The light emitted is coherent (this means that the light waves are continuous without break in
phase over a considerable range in time and space). Lasers can emit light in a very narrow beam in a very
narrow wave length spectrum
©1996–2000 Eurotechnology Japan K. K.

Blackbody radiation
Laser of a light bulb
http://www.eurotechnology.com/

LED

Ultra-Violet Infrared
500 1000 1500nm
wavelength

Blue lasers for optical storage (Bluray)�

  Diffraction limits the size of a focused laser beam to a spot with a
width of the order of the wavelength of the light used, therefore the
wavelengths limits the density of data storage: shorter wavelengths
(blue, violet, UV) enable higher storage density
  In principle, an optical near-ﬁeld microprobe allows a much higher
density of optical storage, however access is VERY slow using current
knowledge

Schematic of information storage on CD-ROM Diffraction spots of
and magneto-optical disc red, green, blue and violet lasers

1 0 0 0 0 0 1 0 1 1 1 1
©1995–2000 Eurotechnology Japan K. K. 800nm 500nm 450nm 400nm



What is a blue light emi ing diode (LED)�
  A light-emitting semiconductor diode (LED) or a laser   A light emitting diode (LED) consists of a stack of n-
diode (LD) both consist of a stack of extremely thin type (left hand side) and a stack of p-type (right hand
and precisely grown semiconductor layers of different side) material, forming a “p-n junction”. Electrons (red)
materials
and holes (green) follow the potential gradient of an
applied voltage and recombine in the region of the p-n
junction. The photons of the emitted light have an
energy similar to the value of the energy gap.


Electron energy
p-GaN(Mg) 0.5µm
electrons
p-Al 0.15 Ga0.85 N (Mg) 0.15µm
n-In0.06 Ga0.94 N (Mg,Zn)

0.05µm
n-Al 0.15 Ga0.85 N (Si) 0.15µm
donors blue emission
4µm
n-GaN (Si) Zn acceptors
GaN Buffer Layer 0.03µm

holes
after: Nakamura, IEEE Circuits
and Devices (1995)
Sapphire Substrate


What is a laser diode (LD)?�
  LASER = Light Amplification by Stimulate Emission of Radiation
➔  Every laser consists of a light amplifier (which amplifies light by stimulated emission) combined with an
optical resonant cavity: Laser = Light Amplifier + Resonant Cavity
➔  In most semiconductor lasers, the light amplifier and the resonant cavity are grown in the same structure,
are strongly interlinked and some components may be shared.
  Light Amplifier: a light amplifier increases the intensity of light in a certain wavelength
range, when it is pumped above a threshold. Above this threshold, “stimulated
emission” occurs. A light amplifier can be “pumped” electrically, optically, or by other
methods. In the case of a semiconductor laser diode, pumping is optically in the first
stages of research, however for devices pumping is almost always electrically
➔  In a semiconductor Laser Diode (LD) the light amplifier consists of a structure similar to a light emitting
diode (LED) with a pn-junction. However, the requirements for accuracy of design, accuracy of growth,
purity, freedom from impurities and crystal defects are much more stringent that for LEDs.
  Resonant Optical Cavity: an optical cavity has certain resonant frequencies. When the
amplification spectrum of a light amplifier within a resonant cavity coincides with the
resonant frequencies of the optical cavity lasing can occur.
➔  The resonant cavity of a semiconductor laser can in the simplest case consist of the cleaved (broken) edges
of the semiconductor, or in more sophisticated cases of multi-layer dielectric mirrors.
➔  A resonant cavity has “eigen-modes” or resonant modes, the transmission spectrum, the reflection
spectrum, spontaneous noise spectrum of a well-formed resonant cavity shows narrow peaks�



Surface emi ing lasers (VCSELs) vs. Edge emi ing lasers�
  Conventional edge emitting semiconductor lasers: the light emission is through the
cleaved edge of the laser. Conventional edge emitting lasers are normally handled
one-by-one are almost impossible to integrate in large numbers.
  Surface emitting laser (Vertical Cavity Surface Emitting Laser = VCSEL). VCSELs
are usually much smaller, can be integrated in large numbers on a substrate wafer,
and are much easier to test one-by-one while still on the wafer
Growth Direction

internal or external reflectors
to form resonant cavity
Reflector
Reflector

active layer
(amplifier)

Surface emitting laser conventional
(VCSEL) semiconductor laser

What is a light amplifier?�
  When light is emitted in an electronic transmission, two types
of emission are possible:
➔  Spontaneous emission: in the case of a laser, spontaneous emission gives
rise to “phase noise” and is not usually desirable. Methods to suppress
spontaneous emission in lasers are desirable and have been proposed by
researchers. In a laser spontaneous emission is necessary to start laser
action, before the lasing threshold is crossed
➔  Stimulated emission: stimulated emission is the emission of photons
stimulated (in resonance) with the electric field of other photons present in
the amplifier. Stimulated emission occurs at sufficiently high intensities, an
usually “population inversion” is necessary, the upper electronic level of the
transition is stronger populated than the lower level. Therefore optical or
electronic pumping is necessary to achieve stimulated emission
  Light entering the amplifier is amplified by resonant emission,
if the amplifier is pumped sufficiently for stimulated emission
to occur and to overcome the losses due to absorption and
scattering


What is a resonant cavity?�
  In optics a resonant cavity is usually called a “Fabry-Perot Cavity”, or “Fabry-Perot Resonator”
  In the simplest case, a resonant optical cavity consists of two highly reflective flat mirrors
which are very accurately parallel. Actually,
  An optical resonant cavity has resonant modes, I.e. the transmission spectrum, the
reflectance spectrum, noise spectrum etc. show very sharp resonances. The higher the quality
and the better the design of the cavity, the sharper these resonances are.
  In a VCSEL (vertical cavity semiconductor laser the resonant cavity is formed by stacks of
layers grown on top of the substrate. The axis of the optical cavity, and laser emission is
perpendicular to the substrate.
  In a traditional edge emitting semiconductor laser the cavity is formed by the cleaved edges
of the laser chip, usually the cleaved edge have to be coated by evaporating thin layers of
dielectric material.
  In semiconductor lasers, the optical amplifier and the resonant cavity are tightly integrated,
strongly interact and influence each other: e.g. during laser operation the electron density in
the structure changes, which changes the refractive index, and both the amplifier and the
resonant cavity become inter-dependent. Therefore in a semiconductor laser, amplifier and
resonant cavity must be designed together, not independently as is sometimes possible in
large gas lasers.


Why Gallium Nitride (AlGaN/InGaN)?�
©1996–2000 Eurotechnology Japan K. K.   AlN, GaN, InN materials all have a
direct bandgap direct band gap, i.e. the optical
6.0 AlN indirect bandgap transitions across the bandgap are
Energy Gap (eV)

“allowed” and therefore much
5.0 MgS stronger than in the case of indirect
bandgaps (which have “forbidden”
4.0 transitions), as in the case of Silicon
ZnS MgSe
Carbide (SiC).
GaN
3.0   Before Nichia brought GaN blue LEDs
AlP ZnSe on the market, commercial blue LEDs
SiC AlAs
2.0 GaP used SiC, which are much less efﬁcient
InN
due to the indirect bandgap
GaAs CdSe
1.0 InP   Before Shuji Nakamura commercialized
Sapphire after: Nakamura, IEEE Circuits GaN blue LEDs it was generally
and Devices (1995)
thought that II-VI compounds were
3.0 4.0 5.0 6.0 the path to blue LEDs and Lasers
however defects in these materials
Lattice Constant (Å) could not be controlled sufﬁciently
and the life-time of the devices was
too short



The Three Key Steps To GaN Devices



Three key steps had to be solved�

 Lattice mismatch
➔  GaN is grown on Sapphire, which has a 15% smaller lattice constant than GaN, and different
thermal expansion, leading to a very high defect density and cracking of the layers when the
structures are cooled down after growth
➔  Akasaki solved this problem by developing AlN buffer layers
➔  Nakamura grew GaAlN buffer layers

 High growth temperature
➔  thermal convection inhibits growth
➔  Nakamura solved this problem with his two-ﬂow growth reactor (this invention by Shuji
Nakamura is at the core of the US$ 600 million law suits before the Courts of Japan
between Shuji Nakamura and Nichia Chemical Industries)

 p-doping was impossible
➔  A semiconductor laser, semiconductor light emitting diode, transistor structures and other
device structures require pn-junctions, I.e. junctions between p-type and n-type materials.
Previous to Akasaki’s work p-type doping of GaN was impossibly
➔  Akasaki demonstrated p-type material which was e-beam annealed
➔  Nakamura found that annealing in Ammonia gas passivated the acceptors and solved this
problem



1. La ice mismatch�
  Choice of substrate
➔  Silicon Carbide (SiC): good lattice matching, very expensive, patent issues
➔  Sapphire: used at present for most devices
➔  Ideally: GaN. However, GaN substrate wafers have not been available. Once they
become available, it is expected that GaN devices grown on GaN will have much better
properties than devices grown on Sapphire with high lattice mismatch
  Sapphire as substrate
➔  15% difference in lattice constants between Sapphire and GaN and very large
difference in thermal expansion initially made growth of devices impossible.
➔  Akasaki solved this issue by designing and growing a AlN buffer layer (Akasaki US-
Patent 4855249, Applied Physics Letters)
➔  Nakamura grew GaAlN buffer layers (Nakamura US-Patent 5290393, Japanese Journal
of Applied Physics)

  Note that CREE generally uses SiC (Silicon Carbide) substrates to grow
GaN devices.
  It would be ideal to grow on GaN substrates, however these are not yet
available in commercial quantities at this date.


1. La ice mismatch�
  Problem: large lattice mismatch and large difference in thermal expansion between Sapphire
substrate and GaN/AlN
  Solution: AlN Buffer layer (Akasaki, US-Patent 4855249, Applied Physics Letters
  Solution: GaAlN Buffer layer (Nakamura, US-Patent 5290393, Japanese Journal of Applied
Physics)
  Ideal solution for the future: GaN substrates (still need to be developed, recent progress
looks promising)

GaN sound zone
dislocation

GaN semi-sound zone (150nm)
lateral growth
faulted zone (50nm) coalescence
buffer layer (GaN or AlN) (50nm)
Sapphire (α-Al2O3)

after: Akasaki (APL, 1986)



3. p-type doping: anneal in Nitrogen�

http://www.eurotechnology.com/   Problem: Pankove (1971 at RCA Laboratories)
6
10 reported metal-insulator-semiconductor Gallium-
Nitride light emitting diodes, but found p-type
5 doping to be impossible
10 Anneal in NH3:
Resistivity (Wcm)

(NH3 dissociates–   Proof of p-type doping: Akasaki (1988 at Nagoya
4 resulting atomic University) found that samples after Low Energy
10 Electron Beam Irradiation treatment (LEEBI)
hydrogen,
showed p-type conductivity. Thus Akasaki
3 passivates
10 demonstrated that in principle p-type doping of
acceptors)
GaN compounds was possible
2
10   Solution: Nakamura (1992 at Nichia, US-Patent
5306662) found the solution to the puzzle of p-
1 type doping (see image on left hand side):
10 ➔  Nakamura found that previous investigators had annealed the
Anneal in N2 samples in Ammonia (NH3) atmosphere at high temperatures.
Ammonia dissociates above 400 Celsius, producing atomic
0
10 hydrogen. Atomic hydrogen passivates acceptors, so that p-
type characteristics are not observed.
Nakamura (J.J.Appl.Phys. 1992) ➔  Nakamura solved this problem by annealing the samples in
Nitrogen gas, instead of Ammonia
0 200 400 600 800 1000
Temperature (C)



Some remaining technology issues�

 Although commercial GaN devices are routinely
produced today, several materials issues still
remain and are under intensive research
investigation:
➔  GaN substrate: at the moment GaN devices are mainly
grown on Sapphire substrates, since GaN wafers of
sufﬁcient size and quality are not available. It is expected
that growth on GaN wafers will lead to much lower defect
densities, because the lattice constant mismatch will be
much smaller
➔  High defect density: it is very puzzling that commercial
GaN devices and particularly lasers operate with defect
densities which are dramatically higher than in comparable
GaAs or Silicon devices. This fact is not understood at the
moment. It is expected that understanding this fact will
lead to improvements to device quality.



White GaN based LEDs


GaN based LEDs cover a wide range of colors�

  Using different material compositions and different
phosphor compositions a wide range of colors can
be produced with LEDs.
  Using red/green/blue combinations a wide range of
color compositions can be produced



Long-Lifetime GaN Lasers



Development of long-lifetime GaN lasers�
  Lasers are much more difficult to develop than LEDs, and in the case of
GaAs-based red and infrared lasers it took many years for the
development of commercial semiconductor lasers.
  The research path in semiconductor laser development is first to develop
lasers which only work at very low temperatures (liquid Nitrogen
temperatures) and under optically pulsed conditions. The development
work leads:
➔  from optical pumping to electrical pumping
➔  from low temperature to room temperature
➔  from pulsed pumping to continuous pumping
➔  from short life-time to long life-time
  Some of the most difficult issues to solve is high-defect density, and
defect migration under the high currents of laser operation
  Nakamura applied Epitaxially Laterally OverGrown (ELOG) GaN substrates
to control defect density for laser structures �


Schematic structure of Nakamura’s blue laser�
  Shuji Nakamura (1997) used ELOG (epitaxially laterally overgrown) GaN substrates
to control defects: seed windows in a SiO2 array control the defects
  ELOG was one of the keys for Nakamura to succeed growth of lasers with 10,000
hours lifetime

4µm
p-GaN:Mg (0.05µm)
Al0.14Ga0.86N/p-GaN:Mg MD-SLS (120 x 25Å/25Å)
p-GaN:Mg (0.1µm)
p-Al0.2Ga0.8N:Mg (0.02µm) p-electrode
n-In0.15Ga0.85N:Si/n-In0.02Ga0.98N:Si MQW (4 x 35Å/105Å) SiO2
n-GaN:Si (0.1µm)
Al0.14Ga0.86N/n-GaN:Si MD-SLS (120 x 25Å/25Å)
n-electrode
n-In0.1Ga0.9N:Si (0.1µm)
n-GaN:Si (3µm)

cracks and
voids
seed-window
SiO2 - mask (4µm)



Schematics of ELOG for defect control�
  Nakamura used the speciﬁcs of defect propagation on ELOG substrates
to fabricate laser structures in low-defect areas of the structure

InGaN-Laser structure
p-electrode n-electrode

n-GaN (3µm)
©2000 Eurotechnology Japan K. K.

cracks and
voids threading
dislocations
GaN (20µm) ELOG-
substrate

SiO2 (1µm)

GaN (2µm)

GaN buffer layer (30nm)
10 µm
(0001) sapphire substrate



Why Did Shuji Nakamura At Nichia
Succeed Where Many MUCH larger
Corporations Failed?



Why did Shuji Nakamura at Nichia succeed where many
MUCH larger multinationals and famous Universities failed?�

  A quick direct answer is, that all other labs (with the exception of Akasaki in Nagoya) looked
at II-VI compounds (ZnSe/ZnS) - and had given up working on Gallium-Nitrides because they
thought it was hopeless. Work on ZnSe/ZnS did not succeed because II-VI compounds have
low stability and are grown at low temperatures. Only Professor Akasaki (at Nagoya University
and later at Meijo University) continued systematic work on GaN over many years.
  Nichia’s Chairman and Founder (Nobuo Ogawa) gave Shuji Nakamura + 2 Assistants YEN 300
Million (approx. US$ 3 Million) to “gamble” on Gallium Nitride. This was about 1.5% of annual
sales for Nichia. In addition, Nakamura had to learn MOCVD growth. For this purpose Nichia
sent Nakamura for one year to the University of Florida to learn MOCVD in Professor
Ramaswamy’s laboratory.
  Large corporations tend to avoid risks more, and tend to take a more conservative approach
to research - even in fundamental research (“jumping on the band-wagon” phenomenon)
  Large corporations and research institutes tend to spend less research budget per researcher
on average, e.g. NTT and other corporations spend on the order of US$ 250,000 to US$
400,000 per researcher per year on average, so that it is very seldom that US$ 3 million + 1
year training in the US is available for the gamble on a new fundamental research project,
which has not yet shown any proven results



Management structure for Shuji Nakamura’s work�
  Typical cooperative research   Shuji Nakamura’s research
management structure of large environment during the most
projects
important phase of his work

© 1998–2000 Eurotechnology Japan K. K.
Diagram of a Typical Research Consortium Project
Evaluation Committee
Diagram of Nichia's
Government Agency
Industrial Technology Council
Hierarchy for the
subsidy and
GaN-Blue Laser

© 1998–2000 Eurotechnology Japan K. K.
Designated R&D investment
Program
Government research
funding Agency Research
Researchers
Government- dispatched
Government Government
Research Joint Research Industry joint from 30
Institutes Research Institute
Agreement research laboratory private
Director enterprises
Several
Government
Research transfer
General
Chairman
Chairman N. Ogawa
Laboratories Scientists

Equal partnership Research
Research Center
Group Joint Research with
Center participation
from industry
Project Leader
Deputy Project Leader
Research scientists Group Leader Research scientists
dispatched/invited Research Scientist dispatched/adopted
Shuji Nakamura
Domestic and overseas academia and research organizations



The Nichia – Shuji Nakamura court case�

  As widely reported in the press internationally there has been a number of court
cases between Shuji Nakamura and Nichia concerning the patents covering Shuji
Nakamura’s research work while he was still at Nichia (he has since moved to
the University of Santa Barbara)
  To our knowledge, the present status is, that the judgments have confirmed
Nichia’s ownership of the key patent which Shuji Nakamura claimed to own
  To our knowledge, the Tokyo District Court has decided that Shuji Nakamura
deserves a 50% share of profits of his invention, and the Court estimated
Nichia’s profits to be on the order of US$ 1.2 billion, so that Shuji Nakamura
would deserve US$ 600 million in reward for his invention. Since Shuji Nakamura
claimed US$ 200 million the court granted his demand in full.
  The court case was taken by Nichia to a higher court, and a court supervised
settlement between Nichia and Shuji Nakamura was reached, where Nichia
agreed to Shuji Nakamura approximately US$ 8 million reward for his inventions
– a dramatically smaller sum than initially awarded by the Tokyo District Court.�



Markets for LEDs



Main applications sectors for white and blue GaN LEDs�

  Trafﬁc signals and other specialty applications
  Automotive head lamps
  Backlighting for liquid crystal displays (LCD)
➔  Mobile phones
➔  Laptop computers
➔  Desktop computers
➔  TVs
  Signage and out-door displays
  General lighting
➔  Industrial
➔  Street lighting
➔  Households
  Other applications



Markets For GaN LEDs
Tra ic Signals and Other Specialty
Lighting



LEDs for tra ic signals�
  Traffic signals together with large area out-
door flat panel displays where the first
applications of GaN LEDs. The reasons are
the initially high price of LEDs
  LEDs are much more suitable for traffic
lights than light-bulbs and in the near future
it is expected that all traffic lights will
operate with LEDs. The main reasons are:
➔  much lower energy consumption
➔  long lifetime (10 years and longer)
➔  better light quality (no filters)
  Trend: at the moment most traffic light
designs use a very large number of LEDs. In
the future it is expected that traffic lights
will be developed to include a much smaller
number of LEDs reducing cost and energy
consumption



Street lights



Displays and signage


LEDs are starting to replace fluorescent tubes in outdoor signage�
  LEDs are starting to
appear in applications
where fluorescent
tubes would have
been used in the past
in outdoor signage
and advertising
applications.
  LEDs consume less
energy, live much
longer, don’t show
flicker when aging,
can be controlled to
show images,
messages and
movies, change color,
and have far more
flexibility�



Architectural lighting
Interior design, shops…



Automotive lighting and headlamps



LEDs for automotive lighting�

  All lighting for cars including
headlights and fog lamps will be soon
replaceable by LED lamps
  At recent Tokyo Motorshows most
leading automotive electrical makers
showed LEDs for car lighting
applications based on red, yellow and
white GaN based light emitting
diodes
  In the future semiconductor LEDs will
enable “intelligent” lighting, e.g.
lighting where the color composition
corresponds to the external lighting
conditions and other built-in
intelligence and control which is
impossible for traditional
incandescent lamps



Mobile phones



Backlights for laptops, PCs and TVs



(D) General Lighting



Markets For GaN Lasers


Markets for GaN lasers�
  The main application for GaN is for data storage and music storage. Due
to the shorter wavelength, violet and UV GaN lasers allow a much higher
data density.
  The next generation DVD standards use blue GaN lasers with a
wavelength of 405nm for reading and writing data. Two competing
standards competed for prominence, however Blue-Ray won the race:
➔  Blu-Ray: promoted by SONY and the Blu-Disc Founders consortium of 11 consumer
electronics companies plus Hewlett-Packard and Dell
➔  HD-DVD (Advanced Optical Disc) promoted by NEC and Toshiba (lost the race…)
  Many other applications exist and are about to be developed, e.g. in the
medical area



Blu-Ray vs. HD-DVD and vs. DVD
Parameter
Blu-Ray
HD-DVD
DVD
Recording Capacity
27 GByte
20 GByte
4.7 GByte
Single layer
(2 hours of HDTV,
13 hours of standard TV)
Recording Capacity
54 GByte
32 GByte
9.4 GByte
Dual layer
Laser wavelength
405nm
405 nm
650 nm

Numerical Aperture
0.85
0.65
0.60

Protection layer
0.1mm
0.6 mm
0.6 mm

Data transfer rate
36Mbps
36 Mbps
11.08 Mbps

Video Compression
MPEG-2
MPEG-2, H.264
MPEG-2
Comments
Blu-Ray Founders
Toshiba, NEC
DVD-Forum
(promoted by SONY)



Patent Issues



Emerging new lighting industry structure



Nichia



Investor perspective:
The Front line - LED makers



Investor perspective:
Equipment makers and other supplies



Trends and projections



Summary


Summary�

  Today’s global lighting industry amounts to approximately US$380bn annually for
lighting fixtures, lamps, electricity and kerosene fuel (in the third world). Energy
consumption, and environmental impact due to CO2 emission and release of
poisons can be much reduced by replacing traditional light bulbs and fluorescent
tubes with GaN based LEDs.
  Legislation, environmental groups, and well positioned companies push for energy-
efficient lighting solutions and reduction of toxic emissions. Incandescent bulbs are
on the way out (“Ban the bulb” movement).
  Japanese researchers at Nichia and Toyoda Gosei in the 1990s invented gallium-
nitride (GaN)-based light-emitting diodes (LEDs), which made it possible for the
first time to replace light bulbs and fluorescent tubes, starting the solid-state
lighting revolution.
  Moore’s law brings semiconductor-innovation cycles to the lighting industry.
  GaN-based LEDs revolutionize the lighting industry, change industry structure and
business models, break established market positions and allow newcomers (Nichia,
Toyoda Gosei, Seoul Semiconductors) to enter the mainstream lighting industry.
  From the investor perspective, in addition to the front-line LED manufacturers,
luminaire makers, manufacturing equipment makers, and materials makers are also
very important, as well as the impact on incumbents.


References (1)�

  Shuji Nakamura, Gerhard Fasol, Stephen J
Pearton “The Blue Laser Diode: The
Complete Story” ISBN 3540665056,
Springer-Verlag, (Second Edition,
September 2000)
  Gerhard Fasol: quot;Room-Temperature Blue
Gallium Nitride Laser Diodequot; SCIENCE, 272,
p. 1751-1752 (21 June 1996)
  Gerhard Fasol: quot;Fast, Cheap and Very
Brightquot; SCIENCE, 275, p. 941-942 (14 Feb
1997)
  Gerhard Fasol: quot;Longer Live for the Blue
Laserquot; SCIENCE, 278, p. 1902-1903 (12
Dec 1997)


References (2)�

  Roland Haitz et al, “The case for a national research program on
semiconductor lighting” (White paper presented at the 1999
Optoelectronics Industry Development Association in Washington, DC, on
6 October 1999)
  Evan Mills, “The US$230 Billion Global Lighting Energy Bill” (manuscript
dated June 2002, and Proceedings of the 5th International Conference on
Energy-Efﬁcient Lighting, May 2002, Nice, France)



Glossary



Glossary-
Light emi ing diodes (LED)�

  At the core of a light-emitting diode (LED) is a p-n junction - a junction of a
p-type-doped and an n-type-doped semiconductor. When a voltage is
applied to the LED, electrons are injected into the n-type side of the LED,
and holes into the p-type side. The injected electrons and holes recombine
at the location of the p-n junction and emit light. The photon energy
(wavelength) of the light corresponds to the bandgap of the
semiconductor material from which the LED is manufactured. Practical red
and infra-red LEDs were invented by Nick Holonyak in 1962 at the R&D labs
of General Electric (GE). (The ﬁrst LED was made in 1907 by H.J. Round,
who was assistant to Guglielmo Marconi at Marconi Company in the UK,
however these ﬁrst LEDs were not practically used.) Until Shuji Nakamura’s
invention and commercialisation of blue LEDs, essentially only red and infra-
red LEDs were commercially available for meaningful applications (weaker
blue LEDs were available before Nakamura’s invention, but their light was
too weak and the lifetime too short for common applications).�



Glossary-
Compact fluorescent lamp (CFL)�

  Compact fluorescent lamps (CFL) are essentially small versions of
the common fluorescent tubes. CFLs use about one-fifth to one-
quarter of the energy of incandescent-light bulbs for a given light
output. Therefore, about 70-80% of the electricity used for
lighting could be saved by replacing incandescent lamps with
CFLs. Although CFLs are substantially more expensive than
incandescent lamps to buy, they have a much longer life.
  The CFL was invented by Edward Hammer at General Electric in
1976. General Electric did not manufacture CFLs at that time.
However, other companies began making and selling them from
1995. Hammer was awarded the IEEE Edison Medal 2002 for
inventing the CFL.
  CFLs contain mercury. In the US, the National Electrical
Manufacturers Association is committed to limiting the amount of
mercury used in CFLs. If broken, CFLs are a health hazard because
of evaporating mercury. When CFLs are disposed of in landfills,
they are likely to be crushed, enabling the mercury to escape into
the atmosphere. Proper recycling is necessary to avoid this
mercury load on the environment.



Glossary�
  General lighting service (GLS)
➔  GLS are lamps for general lighting
  Luminaire (lighting fixture)
➔  The lighting industry uses the term luminaire (lighting fixture) to describe devices used to create artificial
light. A complete luminaire may include some or all of the following components: light source (lamp);
reflector to direct the light; aperture; lens; housing or shell; protective covers; electric ballast (if required,
such as for fluorescent tubes); electronic driver circuitry (as for LED lamps); and wires or connectors to link
the luminaire to a power source.
  Luminous efficacy (luminous efficiency)
➔  The energy efficiency of light sources is the amount of light produced divided by the electricity consumed
and is measured in lumens per Watt (lm/W).
  Gallium Nitride (GaN)
➔  Gallium nitride is a III-V semiconductor crystal with a direct bandgap.
  Solid-state lighting
➔  The light emitters for solid-state lighting (SSL) are solid-state devices, usually gallium-nitride (GaN) light-
emitting diodes (LED) or organic light-emitting diodes (OLEDs).
  Organic light-emitting diodes (OLEDs)
➔  Organic light-emitting diodes have applications in lighting and for flatpanel displays. The first OLED-based commercial
flatpanel displays were introduced for mobile phones in Japan about 2006, and Sony introduced the first commercial,
stand-alone OLED flatpanel display in the autumn of 2007. Development is also progressing on lighting applications of
OLEDs.
  MOCVD
➔  Metal organic chemical vapor epitaxy is a common crystal-growth method used to develop and manufacture GaN
semiconductor light-emitting diodes and lasers. MOCVD allows the growth of device layers with single-atom-layer
precision.



More information:

 Blogs:
➔ http://fasol.com/blog/
➔ http://eurotechnology.com/blog/
 Reports:
➔ http://www.eurotechnology.com/store/

©1996-2008 Eurotechnology Japan K. K. 121


Contact

  Eurotechnology Japan KK
  Shinagawa Intercity Tower A 28F
  2-15-1 Konan, Minato-ku
  Tokyo 108-6028, Japan
  Tel +81-3-6717-4160
  FAX +81-3-6717-4141 and +81-3-5477-7044
  http://www.eurotechnology.com/

  CEO: Gerhard Fasol PHD
  Fasol@eurotechnology.com
  Mobile: +81-90-8594-6291

©1996-2008 Eurotechnology Japan K. K. 122

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