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  • ImplantationIntroduction, Principle, SRIM & TRIM simulation, Thermal Spike Model and Observations from SRIMK. Kamalakkannan,Junior Research Fellow, Ion Beam Research LabDepartment of Nuclear Physics University of Madras, ChennaiKamalakkannan.k.123@gmail.com

    Department of Nuclear Physics

    IntroductionAll the electronic equipment needs Semiconducting materials (p-n type).Doping of impurities (carriers) can be processed by two ways- Diffusion and Implantation.Diffusion is limiting process due to saturation limit and so, we cant make high concentrated carriers.To overcome the diffusion issues of dopants & activation of dopants in material- ion implantation or ion irradiation is the best.In general using particle accelerators to shoot energetic ions on a material is the basic process of implantation and irradiation.Ion implantation is a variety of ion irradiation, as is swift heavy ions irradiation from particle accelerators with very high energies induces ion tracks.

    Department of Nuclear Physics

    Ion Implantation- IntroductionIon implantation- a materials engineering process by which ions of a material are accelerated in an electrical field and impacted into a solid.This process is used to change the physics, chemical and/or electrical properties of the solid- cause many chemical and physical changes in the target by transferring their energy and momentum to the electrons and atomic nuclei of the target material- causes a structural change, in that the crystal structure of the target.Major components are,

    1. Ion source2. Accelerator3. Target chamber

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    Ion Implanter

    ImplantationStructuringThin FilmDepositionEx: Simulation of B ions in SiC 300 keV

    Department of Nuclear Physics

    Important parameters and Typical valuesEq I AjIon Energy(eV)Ion Charge NumberIon Current(A)AAngle of IncidenceE,q,I(cm2)(cm-2s-1)Irradiated AreaIon Flux(cm-2)Ion FluenceRemark: Dose is often used rather than Fluence(although Dose should be a volume energy density) j tj I qeA

    (10 to 500 keV)

    (10 A to ~30 mA)

    (60 to 70)Ion source: Any element including gas in whole periodic table can be chooseTarget: Any target matrix can be choose.

    60 to 70*

    Department of Nuclear Physics

    Ion- Solid interactions

    Multiple collision With electronsE= Energy of ionsm1, Z1 and m2, Z2= Mass No., At. No. of

    Incident ions and Target materialRp= Range of ions

    When energetic ions passes through matter, it looses its energy in two ways,Electronic energy loss due to inelastic collision with electrons(Se) [Electronic stopping]Nuclear energy loss due to elastic collision with atoms of the solid(Sn) [Nuclear stopping]

    Electronic stopping- Dominant at higher energies (tens of MeV & more)- Swift Heavy ion irradiation (SHI)

    Nuclear stopping- Dominant at low energies (tens of keV to MeV)

    m1, Z1 and m2, Z2= *

    Department of Nuclear Physics

    Implantation Simulations- SRIM and TRIMSRIM- TheStopping andRange ofIons inMatter

    - Group of programs which calculate the stopping and range of ions (up to 2 GeV/amu) into matter using a quantum mechanical treatment of ion-atom collisions.TRIM- The Transport of Ions in Matter

    - Most comprehensive program, accept complex targets made of compound materials with up to eight layers, each of different materials. It calculate all kinetic phenomena associated with the ion's energy loss: target damage, sputtering, ionization, and phonon production.Based on a Monte-Carlo calculation which follows the ion into the target, making detailed calculations of the energy transferred to every target atom collision. (multi-layer complex targets) Developed by J. F. Ziegler and J. P. Biersack

    Department of Nuclear Physics

    SRIM- Main PageSRIM and TRIM main menu- shownCan select to use Stopping/Range Table

    and/or to use TRIM simulation for given Ion with given Energy.For SRIM calculationsFor TRIM calculations

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    Stopping and Range Table CalculationSuitable Ions from periodic table Common compounds- List of all materialsSRIM output table button Stopping power units- MeV/(mg/cm2), eV/Angstrom, keV/ um, keV/(ug/cm2), MeV/mm, etc.Energy Low to High

    Department of Nuclear Physics

    SRIM Output TableSRIM output Table for Hydrogen ion in SiC TargetStopping power unit (MeV/ (mg/cm2)Lateral stragglingLongitudinal stragglingProjected rangeElectronic and nuclear stopping powersIon energy

    Department of Nuclear Physics

    SRIM calculations: Energy Loss- Stopping powersStopping powers Sn= dE/dx (Differential energy loss per unit length)Low energy ions 2MeV Inelastic collision electronic energy loss - SHI.Electronic stopping- (Electronic energy loss) Interaction of heavily charged ions with electrons of the target material through Coulomb forces, produce track of ionization and highly kinetic electrons along the path of the primary ion - latent track (Se>Sth) Sth depends on the material.This Electronic stopping forms huge defects (defect clusters, dislocation loop disordered lattice, amorphous etc.)Nuclear Energy loss- Due to elastic collision at lower energies dominant nuclear stopping. This Causes damage and dislocation of nuclei from their lattice sites due to elastic collisions. Always produce lattice defects(Interstitial atoms, anionic or cationic vacancies)

    *

    Department of Nuclear Physics

    Electronic and Nuclear stopping power- Ex: AluminumSRIM prediction of electronic and nuclear stopping power of Al ion in different ion energies.Nuclear stopping power is mostly happened for low energy implantation. The lower value of nuclear stopping power is causes the less defects because the higher nuclear stopping power leads atomic displacements.

    Department of Nuclear Physics

    Thermal Spike ModelThe energy-loss mechanism of the projectile-ion leads to electronic and atomic collision-cascadesThis model replaces the complex process of the atomic collision-cascades by an abrupt temperature rise in an infinitesimal cylindrical volume around the ion trajectory at the time-of-passaget=0.Basic steps of thermal-spike model.Undisturbed solid at temperatureT0. At the time-of-passage the temperature within a small cylinder rises rapidly to a much higher temperatureTT0. After the passage of the ion, defects are thermally created while the thermal energy gradually diffuses away radially from the ion trajectory. Remaining are "frozen" defects.

    Department of Nuclear Physics

    TRIM Input pageSuitable Ion, Energy and Angle Quick or full calculation of tableCommon compounds- List of all materialsOutputs- ion range, Backscattered, Transmitted,Sputtered ions and Collision DetailsIon fluenceTarget layers and Target thickness

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    TRIM Simulation PageTRIM simulation table for B (10 keV) in SiO2/Si bi-layer

    Ion type, Energy and AngleXY Simulation graphDistributions- range, Phonons, Ionization, Energy to recoils, Damage events, Sputtering yields and Collision detailsDamage calculation type- Kinchin- Pease, Full cascades and sputtering

    SiO2/Si*

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    Observations from SRIM and TRIMIon Range (Rp)= Range of ionEx: Boron 100 keV in SiC (Rp= 2010 ) XY Ions SimulationEx: Boron 100 keV in SiC Damage eventsEx: Boron 100 keV in SiC

    (Rp) *

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    Observations from SRIM and TRIMRecoil EnergyEx: Al 300 keV in SiCEnergy Loss due to ionizationEx: Al 300 keV in SiCAlso,3D views of ion damages, Range of ions, Recoil energy, Phonon and Lateral range distribution XY ions simulations- Lateral, Longitudinal view and Vacancies can be calculated

  • Thank You

    60 to 70*m1, Z1 and m2, Z2= *

    *SiO2/Si*(Rp) *