class presentation onmaterials for energy storage and conversion

1. IMPLANTATION TECHNOLOGY
By
Onyekanne Maria Chinyerem (40389)
Onwudiwe Killian ( 40505 )
Ebunu Abraham ( 40501 )
Department Of Material Science And Engineering
Course: Energy Storage
Lecturer: Professor Esidor Ntsoenzok
January 2017
African University Of Science and
Technology Abuja
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2. OUTLINE
 Ion implantation overview
 Description of an Implanter and Working principle
 Innovations in implanter technology
 PIII comparison with standard implanters
 Applications of implanters in semiconductor and non
semi conductor materials
 Innovative application proposals
 Summary and Conclusion
 Appreciation
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3. Background and Introduction
ION IMPLANTATION: what is it ? !!!!!
 process by which energetic impurity atoms can be introduced
into single crystal substrate in order to change its electronic
properties
 In this process the ions are accelerated to high energies and
allowed to impact the silicon surfaces.
 Because of inherent energy they penetrate into the lattice and
are placed inside the silicon lattice.
 low-temperature technique for the introduction of impurities
(dopants) into semiconductors and offers more flexibility than
diffusion.
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4. Background and Introduction
 The idea was proposed by Shockley in 1954, but used for mass
production only after late 1970s.
 Before ion implantation, doping is achieved by diffusion into
the bulk silicon from gaseous source above surface, or pre-
deposited chemical source on wafer surface.
 This approach lacks the flexibility and control required by
CMOS processing, and ion implantation quickly gained
popularity for the introduction of dopant atoms.
 Modern ion implanters were originally developed from particle
accelerator technology. Their energy range spans 100eV to
several MeV (a few nm’s to several microns in depth range).
The implantation is always followed by a thermal activation
(600-1100oC).
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5. IMPLANTERS
 i
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6. DISCRIPTIONS
Typical ion implantation parameters:
 Ion: P, As, Sb, B, In, O
 Dose: 1011 - 1018 cm-2
 Ion energy: 1 - 400 keV
 Uniformity and reproducibility:
±1%
 Temperature: room temperature
 Ion flux: 1012-1014 cm-2s-1
The implanter basis
 Ion source
 Mass analyzer/spectrometer
 Ion accelerator
 Neutral beam trap
 Beam scanners
 Wafer
 Faraday cup
.
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7. WORKING PRINCIPLES
Ion source:
 Desired ion of the dopant species are generated from
ionization of either
 Gas/sputtered solid
 Arsine (AsH3), Arsenic Penta fluoride (AsF5),
phosphine (PH3), di borane (B2H6), boron tri
fluoride (BF3).
 Ionization is achieved by displacing one or two
electrons to give positive ions, since most mass
spectrometer works with positive ions. This process is
carried out at a voltage of ab0ut 25Kv-40Kv
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8. Mass analyzer/spectrometer
A set of magnetic field perpendicular to the
direction of the flow of ionized atom is set up
which will result to a force 𝐹 = 𝑞 𝑉𝑥𝐵 =
𝑀𝑉2
𝑅
(𝑐𝑒𝑛𝑡𝑟𝑖𝑝𝑒𝑡𝑎𝑙 𝑓𝑜𝑟𝑐𝑒)
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Considering this relation, 𝐾. 𝐸 =
1
2
𝑀𝑣2 =
𝑞𝑉(𝑒𝑉), substituting for velocity and equating
with
𝑀𝑉2
𝑅
, we will have
𝑀
𝑞𝑅2, which means that
for any particular mass divided by its charge,
we will get a particular radius of curvature R.
Heavier ions will deflect less than lighter ions
of same charge.

9. Ion accelerator:
The ions that makes it through the mass spectrometer are been accelerated with
a certain voltage (0-175Kv) to ensure the beam of ions travel with a particular
kinetic energy. Since the ions will be travelling through a vacuum, acceleration is
done to increase the kinetic energy of the ions so that they can make through the
vacuum. It is necessary the ions travel through a vacuum to avoid interaction
with oxygen, so as not to cause any reaction.
Neutral beam trap
The neutral beam trap is
composed of an electrostatic
charge bars that allow neutral
charges to pass freely, while the
positively charged are deflected
on to the wafer.
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10. A wafer, also called a slice or substrate, is
a thin slice of semiconductor material, such
as a crystalline silicon, used in electronics
for the fabrication of integrated circuits and
in photovoltaics for conventional, wafer-
based solar cells.
Wafers are formed of highly pure (99.9999999% purity), nearly defect-free
single crystalline material. One process for forming crystalline wafers is known as
czochralski growth invented by the Polish chemist Jan czochralski.
A boule of pure mono crystalline material is hence formed, sliced and polished to form
wafers.
Wafer:
Beam scanning:
The focused ion beam is scanned over the
wafer in a highly controlled manner in order
to achieve uniform doping.
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Faraday cup
.For each positive ion that enters the faraday cup, an electron is
drawn from ground through the current meter to neutralize the
positive charge of the ion. The magnetic field stops outside the
secondary electrons from entering and secondary electrons
produced inside from exiting
The faraday cup is arranged in a process
chamber and beam line, corresponding to
an ion beam shooting position

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13. Advantages of ion implantation
 Extremely accurate dose control
 Tailor made and well controlled doping profile
 large range-of doses-1011 to 1016/cm2
 Low Temperature process
 Wide choice of masking materials (Oxide, PR, Metal)
 Clean environment (Mass separation, vacuum)
 Non-Equilibrium process (conc. Excess of S.S. limit)
Disadvantages of ion implantation
 Highly sophisticated and costly.
 Damage to semiconductor.
 Dopant redistribution during Annealing
 Photoresist heating and hard to strip
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14. Innovations
 Advanced ion implantation technology: takes full advantage of doping and defect
engineering approaches such as device leakage, contact resistance, device and
process variability and of precision materials modification opportunities. It is
necessary that advanced implant tools for sub 20nm node incorporate a variety of
novel features and capabilities
 Safe delivery source (SDS) technology : this is used for the low pressure storage
and dispersing of arsine and phosphine to ion implanters
 Ion implantation with scanning probe alignment: A scanning probe instrument
which integrates ion beams with the imaging and alignment function of a piezo
resistive scanning probe in high vacuum. The beam passes through several
apertures and is accurately set by a hole in the cantilever of the scanning probe.
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Improved single ion implantation with scanning probe alignment :
Improved technique for deterministic placement of single dopant atoms by
single ion implantation with scanning probe alignment. Ions are generated in
a microwave driven ion source, mass analyzed in a Wien filter, and impinge on spin
readout devices after alignment of the ion beam to regions of interest with a
noncontact scanning force microscope
Source: Michael Llg et al, 2012: improved single ion implantation with scanning probe
alignment, journal of vacuum science and technology B

16. Innovation contd.
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Single wafer mechanical scan ion implanter:
This makes use of spot beam technology with ionized molecules which maximizes
the throughput potential and produces uniform implants with fast setup time and
with superior angle control

17. PIII, What is it?
Plasma immersion ion implantation (PIII) is a material
modification technique for treating the near-surface
regions of materials by implanting energetic ions from
a plasma which surrounds the sample.
A number of different terms are used, such as
 plasma source ion implantation (PSII),
 plasma ion implantation (PII),
 plasma immersion implantation (PII),
 plasma-based ion implantation (PBII),
 plasma implantation (PI or p-technique),
 plasma doping (also PLAD™) and Ionclad.
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18. WORKING PRINCIPLES
(source: W. Ensinger 1998)
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 The vacuum chamber can be of two types –diode and triode type depending upon
whether the power supply is applied to the substrate as in the former case or to the
perforated grid as in the latter.
 Plasma source/generator: electron cyclotron, helicon plasma source, capacitively coupled
plasma source, inductively plasma source, DC glow discharge and metal vapour arc ( for
metallic species

19. The plasma envelopes the sample. The sample is negatively biased.
Ions from the plasma are accelerated and implanted into the sample.
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Accelerated ion is extracted from plasma using high voltage pulsed
DC or pure DC supply and targeting them to the substrate or
electrode (cathode for electropositive plasma and anode for
electronegative plasma) with semiconductor wafer placed over it so
as to implant it with suitable dopants.
By means of a pumping system and a gas feed system, an atmosphere
of a working gas at a suitable pressure is created, then a plasma is
generated
Sample holder: The sample to be treated is placed on a sample holder
in a vacuum chamber. The sample holder is connected to a high
voltage power supply and is electrically insulated from the chamber
wall.

20. Conventional Ion Implantation (CII) Verses
Plasma Immersion Ion Implantation (PIII)
Ion
Source
Target
Beam Scanner
Ion Beam
Analyzing
Magnet
Pumping
Ion Beam Implantation using an Accelerator
Plasma Immersed Ion Implantation (PBII, PIII)
Plasma Source
Pumping
High Voltage
Pulser
+
-
Target
Difficult to implant to a large area or a complicated shaped target
For a large area or a complicated shape target.
Simple system structure is another good point.
But,
Not easy to process the target with a narrow hole,
trench, etc., or inside of a pipe.
Non single ion implantation is another demerit
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Properties Standard implanter Plasma immersion ion implanter
Hazardous Not easily operated , is
sophisticated and not easy to
maintain
System is relatively easy to operate and
maintain.
Economical The CII technique is a
sophisticated line of sight
process where a sample can be
doped at room temperature
Capital investment and running cost are
substantially less
Time Consuming Process time is dependent of
sample size and its surface area
Process time is independent of sample size
and its surface area.
Flexible Any shape, size and weight of
sample cannot be processed
Any shape, size and weight of sample
can be processed.
Versatile: Multiple processes cannot be
carried out like implantation,
deposition, etching, etc.,
Multiple processes can be carried out like
implantation, deposition, etching, etc., and
not just semiconductor or metals, even
insulating samples can be treated.
High Throughput: Number of samples cannot be
processed at the same time
Number of samples can be processed at the
same time

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Properties Standard implanter Plasma immersion ion
implanter
Uniformity: The sample surface cannot be
implanted ensuring uniform
dose rate with good
conformity.
The sample surface can be
implanted ensuring uniform dose
rate with good conformity.
Implantation Implantation of multiple
species with multiple charges
is not possible in the same
system
Implantation of multiple species
with multiple charges is possible
in the same system

23. DRAWBACKS
 As no mass separation is possible, there are
always chances of implantation of undesired
impurities present in the plasma into the target,
in addition to the desired dopants.
 Secondary electrons limit the efficiency and
generate x-rays.
 Accurate in situ dose monitoring is tough.
 Implant energy distribution is inhomogeneous.
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24. • Applications of ion implantation
• Doping
• Nitrogen or other ions can be implanted into a tool
steel target (drill bits, for example).
• prosthetic devices such as artificial joints, it is desired
to have surfaces very resistant to both chemical
corrosion and wear due to friction.
• ion beam mixing, i.e. mixing up atoms of different
elements at an interface.
• High speed mosfet.
• Metal parts on heart valves are ion implanted by
carbon to make them biocompatible
• Radioisotopes are implanted in prosthesis for
localized radiotherapy 26/01/2017
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25. Application of PIII
 Micro electronics (plasma doping/PLAD)
 Biomaterials (surgical implants, bio and blood
compatible materials)
 Plastics (grafting, surface adhesion) metallurgy
(hard coatings and tribology)
 Thin metallic coatings on polymeric surfaces
example in electronic circuits, sensors,
electromagnetic shielding and flexible
reflecting surfaces
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26. Innovative applications
 One source multi element surface treatment of materials :
where hardening and surface finishing of a particular material
can be carried out using different ions of different elements
with a single machine, by ionizing at a particular time, the
atoms of the required element. This reduces the need for
several equipment in several applications.
 Dose controlled coating of materials: where the particular
dose for a given surface area can be accurately determined to
influence the desired characteristics and properties onto the
substrate
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27. Summary and Conclusion
 Plasma Immersion Ion Implantation is a potential alternative
that circumvents the limitations of conventional ion
implantation,
 such as the requirements of low ion beam current,
 complicated target handling,
 non-uniform implantation profile and
 ion beam scanning complexity for implantation of three-
dimensional targets.
On account of the maturity and its simplicity, it is believed that
the PIII process technology will find many more applications in
the surface modification and semiconductor industry. Reliable
and non-expensive equipment is still one of the key issues.
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28. References
[1] S.B. Felch et al., Ion implantation for semiconductor devices: the largest use of industrial
accelerators, Proceeding of PAC2013, Pasadena, CA USA, ISBN 978-3-95450-138-0.
http://accelconf.web.cern.ch/accelconf/pac2013/papers/weyb2.pdf 23/01/17
http://www.epj-onferences.org/articles/epjconf/pdf/2016/10/epjconf_MINOS2015_01002.pdf
23/01/17
http://accelconf.web.cern.ch/accelconf/pac2013/talks/weyb2_talk.pdf 23/01/17
http://www-inst.eecs.berkeley.edu/~ee143/fa10/lectures/Lec_08.pdf 23/01/17
Professor N. Esidor, [2017], Lecture Note: Material for Energy and Storage, AUST.
Andre Anders , Lawrence Berckeley Laboratory; Handbook of Plasma Immersion ion
implantation and Deposition
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https://en.wikipedia.org/wiki/Plasma-immersion_ion_implantation 26/01/2017
https://en.wikipedia.org/wiki/Ion_implantation 26/01/2017
Dushyant Gupta. Plasma Immersion Ion Implantation (PIII) Process Physics AND
Technology

29. Thanks So Much For
Listening
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