younes sina, uk huh, ion implantation
DESCRIPTION
Younes Sina, Uk Huh, The University of Tennessee, knoxville, Ion Implantation ,Amorphous region, Annealing, SapphireTRANSCRIPT
Ion Implantation and Annealing of Crystalline Oxides and Ceramic Materials
The University of Tennessee, Knoxville
By : Younes Sina & Uk Huh
C.W. WHITE, L.A. BOATNER, P.S. SKLAD, C.J. McHARGUE, J. RANKIN , G.C. FARLOW and M.J. AZIZ Oak Ridge Natronal Laboratory, Oak Ridge, TN 37831, USA
Material
CaTiO3
SrTiO3
α-Al2O3
Fe implanted α-Al2O3
The unit cell of SrTiO3 consists of a central Ti4+-ion, which is octahedrally coordinated by 6 O2--ions. At the corners of the cube Sr2+-ions are situated
Ti
O
Sr
SrTiO3
Space group: Pm-3m Number: 221 Pearson symbol: cP5 Unit cell dimensions: a = 3.795 Å Atomic positions: Ti at (0, 0, 0) Ca at (1/2, 1/2, 1/2) O at (1/2, 0, 0)
CaTiO3
a≈c
Orthorhombic structure
Al
O
Al2O3
Pb (540 keV, 1x1015 /cm2)
CaTiO3
Crystal Damage
Annealing in air@ 270- 550 ⁰C
TEM
Rutherford Back Scattering(RBS)2 Mev He+
Pb (540 keV, 1x1015 /cm2)
SrTiO3
Crystal Damage
Annealing in air@ 270- 550 ⁰CFrom few minutes to many hours
Rutherford Back Scattering(RBS)2 Mev He+
100110
111
2Al (90 keV, 4x1016 /cm2)& 3 O(55 keV, 6x1016 /cm2)
Al2O3
Crystal Damage
Annealing in air@ 800- 1200 ⁰C
Rutherford Back Scattering(RBS)2 Mev He+
TEM
Fe (160 keV, 4x1016 /cm2 ,L N2)
Al2O3
Crystal Damage
Annealing in Ar@ 800 & 960 ⁰C
Rutherford Back Scattering(RBS)2 Mev He+
TEM
implanted by: Pb (540 keV, 1x1015 /cm2)SrTiO3
100
Liquid Nitrogen
Ion channeling before annealing
Ion channeling after annealing (400 ° C/30 min)
Implanted Pb is substitutional in the lattice after annealing
Epitaxial Recrystallization
Depth of the amorphous region: 1800 Å
implanted by: Pb (540 keV, 1x1015 /cm2)(100) SrTiO3
Ion channeling after annealing 302 ° C/45 min
Epitaxial Recrystallization
Depth of the amorphous region after annealing: 800 Å
Crystallized depth vs. annealing time
implanted by: Pb (540 keV, 1x1015 /cm2)(100) SrTiO3
302 ° C
Induction period
Slope 0.91 Å/s
(100) SrTiO3
implanted by: Pb (540 keV, 1x1015 /cm2)
350 ° C
325 ° C
302 ° C
0.91 Å/s
1.48 Å/s
3 Å/s
Increasing T Increasing Slope
The induction period decreases markedly as the annealing temperature increases.
Crystallization of amorphous SrTiO3 Amorphous →Crystal Transformation
Kinetics of crystallization of Pb- implanted (100) SrTiO3
V(T)=V0e-Q/RT
V00.05 cm/s & Q0.77 eV
Q0.77 eV
Pb (540 keV, 1x1015 /cm2)
SrTiO3
110
111
100
Growth in the (110) direction almost is the same of (100)
Growth in the (111) direction is not linear with time
Crystallization kinetics are not strongly affected by Pb concentration
CaTiO3-High symmetry face
implanted by: Pb (540 keV, 1x1015 /cm2)
Ion channeling spectra after annealing at 425 ° C/15 h in air
Cross section micrograph of Pb (250 keV, 4x1015 /cm2) implanted CaTiO3
implanted by: Pb (250 keV, 4x1015 /cm2)
CaTiO3 (High symmetry face)
Ion channeling spectra in the as-implanted state
Ion channeling spectra after annealing at 500 ° C/h in air
Recrystallization of amorphous CaTiO3 Amorphous →Crystal Transformation
Kinetics of crystallization of Pb- implanted CaTiO3
Q1.3 eV
Q3.76 eV
Crystallization of amorphous Al2O3 Amorphous →Crystal Transformation
1600Å
A few minutes at 800 ° C for 1600 Å γ→α
100 hr at 800 ° C For 800 Å γ→α
γ→α stops before reaching the surface
TEM cross section of →α transition in Al2O3
Annealing at 960 ° C/ 90 min
Crystallization of amorphous Al2O3
Amorphous →Crystal Transformation
implanted by: 2 Al (90 keV, 4x1016 /cm2) & 3 O (55 keV, 6x1016 /cm2) at liquid nitrogen
960 ° C/45 min
Kinetics of →α transition in Al2O3
Temperature dependence of the →α interface velocity in Al2O3
Process Energy/Activation Energy (eV)
γ-Al2O3→α-Al2O3 3.6
Al-O bond energy 4.7
Bulk diffusion of O ions in Single crystal α-Al2O3
6.6
Bulk diffusion of O ions in polycrystalline α-Al2O3
4.8
Bulk diffusion of Al ions in α-Al2O3
5
A micrograph of Fe- implanted Al2O3 (LN2) after annealing at 960 ° C/45 min
Annealing of Fe (160 keV, 4x1016 /cm2 ,L N2) implanted α- Al2O3
960 ° C/45 min
As implanted
Al2O3Fe
Crystal Damage
1500 Å
Fe
Annealing
Fe toward the surface
Crystallization behavior (amorphous →→α ) remains the same but the kinetics of /α
transformation increase by the presence of Fe
The presence of Fe in the amorphous film increases the crystallization kinetics at least by
a factor of 4
Material Direction of the study
Implantation detail
Annealingdetail
Length of Amorphous region
CaTiO3 Low Symmetry (a or c- axis)High symmetry( b- axis)
LN2,Pb 540,250 keV, 4x1015 ,1x1015/cm2
Air500°C/1 hr< 500°C
1100 Å1800 Å
SrTiO3 (100), (110),(111) direction
LN2Pb 540 keV, 1x1015 /cm2
Air400 °C/30 min 302 °C/45 min 305°C325°C
1800 Å
α-Al2O3 C-axis oriented LN22Al (90 keV, 4x1016 /cm2)& 3 O(55 keV, 6x1016 /cm2)
800°C960°C/90 min950°C/45 min
1600 Å
Fe implanted α-Al2O3
C-axis oriented LN2Fe 160 keV, 4x1016 /cm2
Ar800-1200 °C
1500 Å
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