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					ИОННЫЕ ИСТОЧНИКИ
  Проблемы, Достижения,
      Перспективы.

      В.Г.Дудников
     Физика пучков заряженных частиц и
          ускорительная техника

•   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
•    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,
•   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:
•   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
•   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    y
                                   Emission slit
                                   l  0.5 10mm2                           l
                           Emittance             Normalized emittance                          x
            Δx
                            Vx  x   x         E x  Vx    Vx  x / c
                            V y  y   y        E y  V y    V y  y / c              Vz / c

            Δα                    Normalized brightness
                               2I       2 jc 2         2 jMc2  2 jMc2
                           B 2       2           2           2
                              Ex E y  Vx Vy  Wx Wy         Tif

Half spreads of energy of the                 Mc 2 E x
                                                     2                          2
                                                                          Mc2 E y
                                       W x                      Wy 
transverse motion of ions                     2 x 2                       2y 2

                                                2 Mc 2 E x
                                                         2                          2
                                                                           2 Mc 2 E y
Reduced to the plasma emission slit    Wox                      Woy 
                                                       2                     l2

Characteristics of quality of the beam formation:           W0 x  5keV  0.5eV
    Классификация ионных источников
•   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.


                                   Development of Negative Ion Sources

                         2.5
  Negative Ion Current




                          2
                         1.5
          (A)




                          1
                         0.5
                          0
                          1950   1955     1960       1965      1970      1975   1980
                                                     Years
                    Contents
•   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                  6- hollow cathode
                              2- cold cathode emitter     7- filaments
                              3- extractor with          8- multicusp magnetic
                                 magnetic system            wall
                              4- ion beam                9- RF coil
                              5- biased emitter         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

•   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;         4 : H   H  H  H ;
            2 : H   H   H  H ;       5 : H   H  H  H  e

            3 : H  H  H  H ;;
                  
                                         6 : H   H 2  H  H 2  e;
                 H H H H
   Resonance charge -exchange cooling
                      Discharge Stability and Noise

            n,1016 cm-3
              noiseless
    no                                              Diagram of discharge stability
    discharge                                       in coordinates of magnetic field
         n*           noisy                         B and gas density n
            Bmin
                                         B, kG
                                                    μ = eν/m (ν2 + ω2)

    1
μ                          noiseless
0.8

0.6                                              The effective transverse electron
0.4                                              mobility μ vs effective scattering
0.2
                                                 frequency ν and cyclotron frequency ω
    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
                                          et. al. LANL




                     QN2 = 0.46 sccm
Design of SPS with Penning Discharge
Discharge voltage

                     Noiseless operation
Discharge current



                       100 Hz
Extraction voltage




Extraction current
                     Tested for 300 hs of
                     continuous operation




  H- current after
 magnetic analyzer
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: dvg43@yahoo.com

     ICIS 2003, Dubna, Russia
        September13, 2003
                       Contents

•   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

•   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

•   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; 2-
                           cathode holder; 3-
                           cathode; 4- gas
                           discharge chamber;
                         • 5-anode; 6-plasma;
                           7-plasma plate; 8-
                           emission slit; 9-
                           small 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

                         •   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

•   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                  6- hollow cathode
                             2- cold cathode emitter     7- filaments
                             3- extractor with          8- multicusp magnetic
                                magnetic system            wall
                             4- ion beam                9- RF coil
                             5- biased emitter         10- magnetic filter
Schematic of B- SPS, 0.5 mA
                   •   1- cooled flange with electric
                       and gas feedthroughs;

                   •   2- high voltage vacuum
                       insulator;
                   •   3- vacuum chamber;
                   •   4-gas discharge chamber-
                       cathode;
                   •   5 anode;
                   •   6- emitter;
                   •    7- high voltage extractor
                       insulators;

                   •   8- magnet; 9- base plate with
                       extractor; 10- ion beam; 11-
                       suppression grid; 12- collector
                       liner; 13- collector; 14-
                       permanent magnets; 15-
                       pepper-port emittance
                       registration; 16- analyzer
                       magnet with mass spectrum
                       registration.
Compact HNISPS, 0.5 mA
                 •   1-Anode; 2- Hollow Cathode;

                     3- Anode Insulator;
                 •   4- Spherical Emitter;

                 •   5- Front Plasma Plate with
                     emission aperture;
                 •   6- Emission Aperture;

                 •   7- Negative Ion Flux;
                 •   8- Bottom Plate; 9- Discharge
                     Chamber Holders- Coolers; 10-
                     Insulator of Emitter’s Holder;
                     11- Emitter’s Holder-cooler; 12-
                     Gas delivery tube; 13- Cesium
                     Supply; 14- Insulating tube of
                     emitter; 15- Emitter’s screen.
Schematic of ALPA Source
                  •   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.

				
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