ИОННЫЕ ИСТОЧНИКИ

ИОННЫЕ ИСТОЧНИКИ
Проблемы, Достижения,
Перспективы.
В.Г.Дудников
Физика пучков заряженных частиц и
ускорительная техника
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American Physical Society-APS, Beam Division. (APS.org)
Budker Institute of Nuclear Physics (BINP),(inp.nsk.su)
G.I.Budker (1918-1977),
Электрон-позитронные встречные пучки 1965,
Протон- антипротонные встречные пучки
Частота столкновений- светимость
Нужна высокая плотность пучков в месте встречи: высокая
яркость пучков
G.I.Budker (1918-1977)
Получение пучков с высокой яркостью
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Для получения пучков с высокой яркостью были
разработаны:
Перезарядная инжекция протонов в циклические
ускорители (Charge-exchange (stripping) injection, BDD,
Budker,Dimov,Dudnikov, 1965)
Электронное охлаждение ( Electron cooling, Budker, Skrinsky,
Dikansky,Parkhomchuk,...)
Поверхностно-плазменные источники отрицательных ионов
(Surface-Plasma Sources (SPS),BDD, Belchenko, Dimov,
Dudnikov) с высокой яркостью пучков.
Стохастическое охлаждение (Stochastic cooling,
CERN,NP,W,Z)
Hadron Colliders
• Proton Antiproton Collider 2x1 TeV, Tevatron,
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Perimeter L=6km, FNAL.gov
Head of Tevatron Department- Vladimir Shiltsev,F.F.NGU
accelerators
Proton Proton Collider LHC- CERN. CERN.sh
CERNcurer
Friendsofthensu.org
Vladimir Balakin (1968)- director of BINP division
& Vladimi Shiltsev (1990), Head of TEVATRON
Department
40 лет Ф.Ф. НГУ в Chicago, FNAL & ANL
ION SOURCES
• Ионный источник- Ion Source- Устройство для создания
ионных пучков – пространственно сформированных
упорядоченных потоков ионов, со скоростями много
большими тепловых.
• Ионы: заряженные частицы, взаимодействуют с полями,
гибкое управление.
• Положительные Н+ = Н-е, потенциал ионизации I~10eV,…
• Отрицательные Н- = Н+ е, электронное сродство А~1eV
• Ионизация: электронным ударом,поверхностная,…
• Прилипание электронов:радиационное, диссоциативное,
на поверхности,…
Применения ИИ:
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Ускорители, Ионная имплантация, Масс-спектрометрия,
Разделение изотопов,
Инжекторы в УТС,
Ионное распыление, напыление пленок, ионное
травление, микро-нано обработка( micro/nano fabrication),
Плазменные технологии ( Проф. Ю.И.Бельченко ),
“ Подвал “
Конференции:
International Conference Ion Sources (ICIS2003),…
Electron, photon,ion beam, JVSTech.
Google.com, yahoo.com Ion Sources, Ion implantation,
ICIS2003, ….
История
• E. Goldstein 1886, Первое наблюдение ионного пучка,
Каналловые лучи,
• Обнаружение изотопов, Астон.
• Электромагнитное разделение изотопов, Lawrenc,
• Ионная имплантация в полупроводники,
• Ускорители, Перезарядная инжекция, ППИ(SPS),
• УТС,
• Микро-нано технологии.
Параметры ионных пучков,
ПРОБЛЕМЫ
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Энергия ионов W=eU.
Заряд: еZ
Интенсивность- ток ионного пучка I, рА- кА,
Плотность тока J=I/S.
Разброс энергий поперечного движения(поперечная
температура Тt ~1eV)
Эмиттанс ( поперечный фазовый объем) ε= r vt .
Яркость пучка: интенсивность/ (эмиттанс)2 I/ε2 ~ J/Tt .
Energy spread ΔW/W
Perveance P= I/U3/2 .
Lifetime
Cost for Ownership
Emittance, Brightness, Ion Temperature
δ
Emission slit
  l  0.5 10mm2
Δx
Δα
y
l
Emittance
Normalized emittance
Vx  x   x
V y  y   y
Ex  Vx    Vx  x / c
E y  Vy    Vy  y / c
x
  Vz / c
Normalized brightness
2I 
2 jc2
2 jMc 2
2 jMc 2
B 2
 2
 2
 2
 Ex E y  Vx Vy  Wx Wy
 Tif
Half spreads of energy of the
transverse motion of ions
Reduced to the plasma emission slit
Mc 2 E x2
Wx 
2x 2
Wox 
Wy 
2Mc 2 E x2
Characteristics of quality of the beam formation:

2
Mc 2 E y2
Woy 
2y 2
2 Mc 2 E y2
l2
W0 x  5keV  0.5eV
Классификация ионных источников
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Плазменные: образование ионов в плазме А+е= А+ +2е
С газовым разрядом постоянного тока, ВЧ,СВЧ,…
Однозарядных, Многозарядных ионов, Отрицательных
С поверхностной ионизацией: положительной,
отрицательной, с полевой эмиссией,…
Поверхностно-плазменные (Surface-Plasma Sources)
(SPS)
Перезарядные,
Лазерные
Электроннопучковые (EBIS)
Стационарные(DC,CW), Импульсные.
Polarized ions.
Системы формирования ионных пучков
• Формирование ионных пучков- ускорение и фокусировка
электрическим полем между эмиттером и экстрактором.
• Самосогласованная граница плазмы.
• Моделирование (Computer simulation).
• Пространственный заряд, дефокусировка.
• Транспортировка интенсивных пучков, фокусирующие
системы.
• Компенсация пространственного заряда.
RF Ion Source
Разделение изотопов
Budker Institute of Nuclear Physics
Arc- discharge- based ion source
DNBI arrangement at TCV
Intensity of Negative Ion Beams: 1971-discovery of
Cesium Catalysis.
Negative Ion Current
(A)
Development of Negative Ion Sources
2.5
2
1.5
1
0.5
0
1950
1955
1960
1965
Years
1970
1975
1980
Contents
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Introduction.
• Historical remarks.
• Change-Exchange injection.
• Negative ion production in surface- plasma interaction.
Cesium catalysis.
• Surface Plasma Sources- SPS.
• Discharge stability noiseless operation.
Charge-exchange cooling. Electron suppression.
• Beam extraction, formation, transportation.
Space charge neutralization. Instability damping.
• SPS design. Gas pulser, cesium control, cooling.
• SPS life time. SPS in accelerators.
• Further development.
• Summary.
• Acknowledgment.
History of Surface Plasma Sources Development
(J.Peters, RSI, v.71, 2000)
First version of Planotron (Magnetron) SPS,
INP, 1971, Beam current up to 300 mA, 1x10mm2
Schematic Diagrams of Surface Plasma Sources
with Cesium Catalysis of Negative Ion formation
(a) planotron (magnetron) flat cathode
(b) planotron geometrical focusing (cylindrical
and spherical)
(c) Penning discharge SPS (Dudnikov type SPS)
(d) semiplanotron
(e) hollow cathode discharge SPS with
independent emitter
(f) large volume SPS with filament discharge
and based emitter
(g) large volume SPS with anode negative ion
production
(h) large volume SPS with RF plasma
production and emitter
1- anode
2- cold cathode emitter
3- extractor with
magnetic system
4- ion beam
5- biased emitter
6- hollow cathode
7- filaments
8- multicusp magnetic
wall
9- RF coil
10- magnetic filter
Large Volume Surface-Plasma Sources
Neutral Beam Injector for Tokamak,
40A, 0.5 MeV
22.1 Development of a Large Volume Negative Ion Source for ITER
Neutral Beam Injector
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Y. Okumura, T. Amemiya, T. Iga, M. Kashiwagi, T. Morishita, M. Hanada, T.
Takayanagi, K. Watanabe, Japan Atomic Energy Research Institute, Japan
• Design of the large negative ion source for the neutral beam injector in
International Thermonuclear Experimental Reactor (ITER) has been completed.
The ion source is required to produce hydrogen/deuterium negative ion beam of
40MW(40A, 1MeV) for pulse duration of more than 1000s. The ion source is a
cesium-seeded volume source, consisting of a multi-cusp plasma generator and a
five-stage electrostatic accelerator. Negative ions are extracted and accelerated in
multi-aperture grids, where 1300 apertures of 14mm in diameter is distributed
over the area of 60cm x 160cm. Multiple beamlets extracted from the grids
should be focused precisely toward a focal point to achieve a high geometrical
efficiency of the neutral beam injector. Beam optics in the multi-stage
electrostatic accelerator has been studied in JAERI 400keV H- ion source. It was
demonstrated that convergent beamlets having a divergence of 3mrad are
produced and focused within an accuracy of several mrad. Beamlet-beamlet
interaction is observed and the experimental result agrees well with the 3D ion
trajectory simulation. Negative ion beam acceleration in a 1MeV prototype
accelerator is in progress using a new vacuum insulated accelerator column.
Latest status of the R&D for ITER ion source is presented.
H- Detachment by Collisions with Various Particles
and Resonance Charge-Exchange Cooling
 1 : H   e  H  2e;
2 : H   H   H  H ;


 33 : H
H   H
H
HHHH ; ;
Resonance charge -exchange cooling
 4 : H   H  H  H ;
5 : H   H  H  H  e
 6 : H   H 2  H  H 2  e;
Discharge Stability and Noise
n,1016 cm-3
noiseless
no
discharge
n*
noisy
Bmin
Diagram of discharge stability
in coordinates of magnetic field
B and gas density n
B, kG
μ = eν/m (ν2 + ω2)
μ
1
noiseless
0.8
The effective transverse electron
mobility μ vs effective scattering
frequency ν and cyclotron frequency ω
0.6
0.4
0.2
0
0
0.5
1
1.5
2
2.5
3
ν/ω
Discharge Noise Suppression by Admixture of Nitrogen
P.Allison, V. Smith,
no N2
QN2 = 0.46 sccm
et. al. LANL
Design of SPS with Penning Discharge
Discharge voltage
Noiseless operation
Discharge current
100 Hz
Extraction voltage
Extraction current
H- current after
magnetic analyzer
Tested for 300 hs of
continuous operation
Fermilab Magnetron with a Slit Extraction
Discharge Parameters and Beam Intensity
in Fermilab Magnetron
0
time, mks
200
0
80
0
time, mks
100
Beam Intensity vs Discharge Current and
Extraction Voltage in Fermilab Magnetron
ИОННЫЕ ПУЧКИ ДЛЯ ТЕХНОЛОГИЙ
В. Г. ДУДНИКОВ
Ion Beams for Technology
Vadim Dudnikov
Brookhaven Technology Group, Inc.
e-mail: [email protected]
ICIS 2003, Dubna, Russia
September13, 2003
Contents
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Introduction.
Ion Beam Technologies: Ion Implantation. SOI. Deposition. Etching.
Micro/Nano fabrication.
Ion Implantation.
Ion Sources for Ion implantation.
Beam line optimization.
Space charge neutralization.
Plasma Accelerators.
Summary.
Acknowledgment.
Ion implantation in semiconductor industry
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Major Players:
Axcelis (former EATON)
VSEA( former Varian)
Applied Materials
High Energy(1-5 MeV):
Tandem(negative ion), Linac(MC).
Low Energy Beam
Plasma Immersed Implantation
Peter Rose in IBIS-Krytec
Silicon on Insulator (SOI)
SMART CUT, SOITEC
High dose Proton implantation and
ION IMPLANTATION for SEMICONDUCTOR
Ion implantation has become the technology preferred by
industry to dope semiconductors with impurities in the large
scale manufacture of integrated circuits. Ion dose and ion
energy are the two most important variables used to define an
implant step. Ion dose relates to the concentration of
implanted ions for a given semiconductor material. Typically,
high current implanters (generally greater than 10 milliamps
(mA) ion beam current) are used for high dose implants,while
medium current implanters (generally capable of up to
about 1 mA beam current) are used for lower dose
applications.
Ion energy is used to control junction depth in
semiconductor devices. The energy levels of the ions
which make up the ion beam determine the degree of
depth of the implanted ions. High energy processes
such as those used to form retrograde wells in
semiconductor devices require implants of up to a
few (1-5) million electron volts (MeV), while
shallow junctions may only demand energies below
one thousand electron volts (1 KeV).
Now is most important low energy implantation
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Upgrading of existing implanters
Space Charge Neutralization (SCN)
Molecular ions: Decaboran B10H14, B2H6, As2,
J= A U3/2/M1/2 .
A typical ion implanter comprises three sections or
subsystems:
(i) an ion source for outputting an ion beam,
(ii) a beamline including a mass analysis magnet for mass
resolving the ion beam,
(iii) a target chamber which contains the semiconductor wafer
or other substrate to be implanted by the ion beam.
The continuing trend toward smaller and smaller
semiconductor devices requires a beamline construction
which serves to deliver high beam currents at low energies.
The high beam current provides the necessary dosage levels,
while the low energy levels permit shallow implants.
Source/drain junctions in semiconductor devices, for
example, require such a high current, low energy application.
High current low energy implanters
Typical high current implanter for semiconductor
Bernas, Small Anode Ion Source for
Implanter
• B, P, As, Ge,…
• 1,4- filaments; 2-gas discharge
chamber; 3- emission slit; 5-screen;
• 6-cathode insulator; 7-small anode;
• 8-anode insulator.
• SDS- Gas system: safe delivery
system.
• Suppliers of parts: Glemco.com
• egraph.com
Schematic of beam extraction and 2D simulation
• Three electrode
extraction system
• 5mm/div
• slit 0.2x9 cm
• Current 60mA,
• B, BF2, F,
• Ux=3 kV
• Us=15 kV
Boron beam current VS beam energy
• Analyzed boron 11
beam current from
Bernas and SAS
sources with space
charge
neutralization by
electronegative
gases
Indirect heated cathode ion source, MC
• 1-filament; 2cathode holder; 3cathode; 4- gas
discharge chamber;
• 5-anode; 6-plasma;
7-plasma plate; 8emission slit; 9small anode;
Implanter beam line with Space Charge
Neutralization
• Electronegative
• gas and plasma for
• space charge
neutralization
• VESUVII-8M
Patent for Space Charge Neutralization with EN Gas
Beam line with advanced space charge
neutralization
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1-ion source;
2-ion beam;
3-gas injector;
4-magnetic pole;
5-ion beam;
6-gas injector;
7-beam scaner;
8-beam damp.
High Current Implanter
Low Energy Beam instability
• Boron ion
beam with
energy 5
keV
Effect of SCN with electronegative gas
• Ib-ion beam
current
• p-vacuum
gauge
reading
• Iex-extractor
current
• Q-gas flux
• BF3,SF6,CF4
Low energy beam after analyzer
Boron ion beam
with energy 3 keV,
up to 4 mA
Ion beam after analyzer after gas injection
• Boron ion
beam 3 keV
• Q of BF3
• 4 ccm.
Boron beam mass spectrum, 5 keV
• Mass
spectrum
for
different
gas
injection
Damping of beam instability by gas injection
• Boron ion beam 5 keV
• for different flux of
BF3 Q, ccm(N2)
EATON Patent for Space Charge Neutralization
Low energy beam improvement
SCN by
electronegative
gas
Improving of low energy Boron beam
• Advanced
SCN
As beam improving by SCN and molecular
ions
• Molecular
ions used
for increase
a low energy
beam
intensity:
• As2,
• Decaboran
• B10H14
ETCHING, DEPOSITION, Micro/Nano Fabrication
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Major Players:
Veeco Instruments,Inc
Applied Materials
Advanced Energy Industrial,
…..
Kaufman, RF grid extraction Ion Sources
End Hall IS,
Anode Layer Plasma Accelerators (ALPA)
Schematic Diagrams of Surface Plasma Sources with Cesium
Catalysis of Negative Ion Formation
(a) planotron (magnetron) flat cathode
(b) planotron geometrical focusing (cylindrical
and spherical)
(c) Penning discharge SPS (Dudnikov type SPS)
(d) semiplanotron
(e) hollow cathode discharge SPS with
independent emitter
(f) large volume SPS with filament discharge
and based emitter
(g) large volume SPS with anode negative ion
production
(h) large volume SPS with RF plasma
production and emitter
1- anode
2- cold cathode emitter
3- extractor with
magnetic system
4- ion beam
5- biased emitter
6- hollow cathode
7- filaments
8- multicusp magnetic
wall
9- RF coil
10- magnetic filter
Schematic of B- SPS, 0.5 mA
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1- cooled flange with electric
and gas feedthroughs;
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2- high voltage vacuum
insulator;
3- vacuum chamber;
4-gas discharge chambercathode;
5 anode;
6- emitter;
7- high voltage extractor
insulators;
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8- magnet; 9- base plate with
extractor; 10- ion beam; 11suppression grid; 12- collector
liner; 13- collector; 14permanent magnets; 15pepper-port emittance
registration; 16- analyzer
magnet with mass spectrum
registration.
Compact HNISPS, 0.5 mA
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1-Anode; 2- Hollow Cathode;
3- Anode Insulator;
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4- Spherical Emitter;
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5- Front Plasma Plate with
emission aperture;
6- Emission Aperture;
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7- Negative Ion Flux;
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8- Bottom Plate; 9- Discharge
Chamber Holders- Coolers; 10Insulator of Emitter’s Holder;
11- Emitter’s Holder-cooler; 12Gas delivery tube; 13- Cesium
Supply; 14- Insulating tube of
emitter; 15- Emitter’s screen.
Schematic of ALPA Source
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1-anode;
2-cathode;
3-gap;
4- central pole;
5-ion beam;
6-yoke;
7-gas feed;
8-p.magnet;
9-cooling;
• 10- insulator.
Photograph of ALPA Source
Oxigen Ion beam from ALPA source
BDD, ICIS2001, ALPA source
Advantages of ALPA Sources
Summary
• Modern trend in ion beam technology, as ion implantation for
semiconductor, etching, deposition, are considered.
• Mass production of Silicon on Insulator (SOI) by Smart Cut
Technology use high current proton implanters. Smart Cut Technology
now main method of SOI production.
• Transition to SOI is limited needs of high energy implantation.
• Now is most important high current low energy ion implanters.
Methods for increase intensity and stability of low energy beams are
discussed.
• Development of ion sources for implanters, improving of space charge
neutralization, instability damping are components of implanters
upgrading.
• Anode Layer Plasma Accelerators (ALPA) for broad spectrum of ion
beam application now become very popular and many companies start
development and manufacturing of ALPA sources.