ieae crp f1.20.16. ion beam modification of insulators
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IEAE CRP F1.20.16. Ion Beam Modification of Insulators 3 rd RCM, Chiang Mai, Thailand, 10-14 Dec 2007 Ion Beam Modification of Sputtered Metal-Nitride Thin Films - a Study of the Induced Microstructural Changes VINČA Institute of Nuclear Sciences, Belgrade, Serbia - PowerPoint PPT PresentationTRANSCRIPT
IEAE CRP F1.20.16. Ion Beam Modification of Insulators3rd RCM, Chiang Mai, Thailand, 10-14 Dec 2007
Ion Beam Modification of Sputtered Metal-Nitride Thin Films -a Study of the Induced Microstructural Changes
VINČA Institute of Nuclear Sciences, Belgrade, Serbia
- project started in May 2006 -
researchers:
Momir Milosavljević (Dr)Davor Peruško (PhD student)Maja Popović (MSc student)Mirjana Novaković (MSc student)
other co-workers in the group:
Velimir Milinović (Dr – Goett)Bane Timotijević (Dr-Surrey)
Investigations on this Project- started in May 2006 -
• Ion beam modification of Cr-N and TiN thin films on Si reactively sputtered, ~ 250 nm, implanted with 120 keV Ar
• Deposition of TiN coatings on pre-implanted stainless steel, 40 KeV nitrogen, 1.3 m TiN coatings subsequently deposited
• Ion beam modification of Al/Ti and AlN/TiN multilayers on Si, with 200 keV Ar or N2 ions
VINČA Institute ofNuclear Sciences
Lab for Atomic Physics
- research facilities used for this Project -
Balzers SPUTTRON II thin film deposition systemd.c. and r.f. sputtering, four target, rective deposition
Ion implanter – HV terminal 500 kV, Nielsen or RF ion sources for gases and solids, beam current 1-100 A,
scanned target area up to 5 cm diameter
2MV Van de Graaff ion acceleratorRBS – beam line in preparation
TEM – Philips EM400T 120 keV
Multimode NanoScope 3D, STM, AFM, MFM…
VEECO NANOINDENTER
Results to be presented- from the start of this project -
• Ion beam modification of Cr-N and TiN thin films on Si reactively sputtered, ~ 250 nm, RT or 150oC, different N2 pressure, implanted with argon at 120 keV, to 1x1015 and 1x1016 ions/cm2
• Deposition of TiN coatings on pre-implanted stainless steel
– AISI C1045 steel substrates implanted with 40 KeV nitrogen, to 5x1016 – 5x1017 ions/cm2, 1.3 mm TiN coatings subsequently deposited
• Ion beam modification of Al/Ti and AlN/TiN multilayers on Si, with 200 keV Ar or N2 ions, to 5x1016 – 2x1017 /cm2
100 200 3000
2000
4000
6000
8000
10000
12000
Si
NAr
Cr
Cr-N a.d. ~ 28% N
~ 38% N
~ 50% N
2e-4 3.5e-4 5e-4
Cou
nts
Channel
RBS spectra of as-deposited films as a function of N2 pressure (Goettingen)
Ion beam modification of Cr-N films on Si
100 200 3000
2000
4000
6000
8000 a.d. PN
2
5x10-5 mbar
Ar
Cr
N
Si
data fit
Cou
nts
Channel
RBS analysis of as-deposited and implanted Cr-N/Si
200 400 6000
2000
4000
Ba
cksc
att
eri
ng
yie
ldChannel
as deposited
1x1016 ions/cm2p
N2=2x10-4 mbar
Ar
30 40 50 60 700
50
100
150
200
250
(220)CrN
(311)Si
as depositedp
N2=5x10
-4 mbar, RT
CrN
(200)
CrN(111)
Inte
nsity
(a.
u.)
2 (degree)
30 40 50 60 700
50
100
150
200
250
CrN(220)
doseAr
+=1x1015
ions/cm2
pN2
=5x10-4
mbar, RT
(111)CrN
CrN(200)
Si(311)
Inte
nsity
(a.
u.)
2 (degree)
30 40 50 60 700
50
100
150
200
250
(311)Si
(111)
(200)
(220)CrN
CrN
CrN
doseAr
+=1x1016
ions/cm2
pN2
=5x10-4
mbar, RT
Inte
nsity
(a.
u.)
2 (degree)
XRD analysis => for PN2 = 2 and 3.5x10-4 mbar, Cr2N is formed for PN2 = 5x10-4 mbar, CrN phase forms
as-deposited 1x1015 Ar/cm2 1x1016 Ar/cm2
analysis of samples deposited at 150oC, PN2 = 5x10-4 mbar,implanted to 1x1015 and 1x1016 Ar/cm2
X-TEM analysis of Cr-N deposited at 150oC, PN2 = 5x10-4 mbar
as-deposited 1x1015 Ar/cm2 1x1016 Ar/cm2
0 2 4 6 8 10100
150
800
850
3.5x10-4mbar
2x10-4mbar
Ion fluence (x1015 ions/cm2)
5x10-4 mbar
Re
sist
ivity
(cm
)
Sheet resistance measurements of Cr-N films
RT
1500C
Samples deposited at 150oC
100 200 3000
2000
4000
6000
Ar
Ti
N
Si
data fit
Co
unt
s
Channel
RBS analysis of as-deposited films (Goettingen)
0 2000 40000
20
40
60
80
100
Con
cent
ratio
n (
at %
)
Depth (x1015
at/cm2)
Ti N Ar Si
(b)
Ion beam modification of TiN films on Si
TEM analysis of TiN deposited at RT
as-deposited
implanted1x1016Ar/cm2
0
50
100
150
200
0
50
100
150
30 40 50 60 70 800
50
100
150
TiN
TiNTiN
TiN
Inte
nsity
(a.
u)
(111)
(200)(220)
(311)
Si(311)
(a)
2(degrees)
TiN
TiNTiN
TiN(311)
(220)(200)
(111)
(311)(b)Si
(c)
(111) (200) (220)
(311)
TiN TiN TiN
TiN
Si(311) 0 2 4 6 8 10
50
60
70
80
90
Re
sist
ivity
(c
m)
Ion fluence (x1015ions/cm2)
RT 150oC
Sheet resistance measurements
XRD analysis of TiNdeposited at 150o C
Conclusions for Cr-N and TiN films
• Ion irradiation induces local rearrangements in the layer structure, the polycrystalline structure being retained
• Original columns become disconnected, nano-particles of the same phase are formed
• The resulting structures contain more crystalline defects (point defects in larger grains, nano-particles) which induce higher electrical resistivity
• No measurable changes in surface roughness were found• Sheet resistance measurements can be useful to interpret the
results of structural analysis
20 30 40 50 60 70 80 90 100 110
0
10000
Fe2N
Fe2N
Fe2N
Fe2N
Fe2N
2 (degree)
(c)
(110)
(200)(211)
(220)
Fe2N
(210)
(002)
(211)
(212)
(400)
(213)
0
10000
Fe2NFe
2N
Fe2N
Fe2N
FeFe
Fe
Fe
Fe
Fe
FeFe
(b) Fe2N
(210)
(002)
(211)
(212) (400)
0
10000
(220)(211)
(200)
(110)
FeFe
(a)
Fe(110)
(200)(211) Fe
(220)
Nitrogen pre-implantation of steel substrates shallow implants at 40 keV
standard XRD of TiN coating
GXRD of implanted substrate
unimplanted
2x1017
5x1017
30 40 50 60 70 80 900
100
200
300
400
Fe
FeTiN
TiN
TiN
TiN
Re
lativ
e In
ten
sity
2 (degree)
TiN(111)
(200)
Fe(110)
(220)(200)
(311)
(222)(211)
0 1x1017 2x1017 3x1017 4x1017 5x1017
500
1000
1500
2000
2500
3000 substrate substrate with coating
Mic
roha
rdne
ss (
MP
a)
Ion Fluence (ions/cm2)
Microhardness measurements
Conclusions for substrate pre-implantation
• Low energy, high fluence nitrogen implants induce formation of Fe-nitrides in the near surface region of the substrates
• Substrate pre-implantation influences preferred orientation of the grown TiN crystal grains
• The layers deposited on pre-implanted substrate exhibit a higher microhardness
• Total increase of the substrate microhardness after nitrogen pre-implantation and TiN deposition is up to more than eight times
Ion beam modification of multilayered thin film structures
nano-scaled multilayered structures TiN/Ti, TiN/AlN, etc, offer numerous advantages over single layer components
higher performance at much lower thickness, higher strength and hardness due to multiple interfaces, can form super lattices, graded structures, etc
ion beams can be useful for preparation and modification in the processes such as IBAD, plasma immersion, or ion implantation – homogenization, more dense and less porous structures
High fluence nitrogen implantation in Al/Ti multilayers on Si
10 alternative Al and Ti layers, deposited by ion sputtering in a single vacuum run, total thickness ~ 270 nm
200 keV N2+ ions, to 1x1017 and 2x1017 at/cm2, Rp ~ mid depth
aim – to study interface mixing and formation of metal-nitrides
N2+ ions
Al/Timultilayers
Si
Experimental work
Thin film deposition, ion implantation and TEM analysis – Vinča Inst
RBS analysis, 1.5 MeV He+ beam, two detectors, 148.2o scatt in ibm and172.8o in cornel geometry, Data Furnace – University of Surrey
AES primary electron energy 3 keV, two Ar ion guns for sputtering off 5x5 mm2 of the sample area – Jožef Stefan Inst, Ljubljana
100 150 200 2500
2000
4000
6000
8000
10000
12000
14000
O
N
Si
Al
Ti
as-dep 1e17 N 2e17 N
Cou
nts
Channel
RBS experimental spectra (Surrey)
100 150 200 2500
2000
4000
6000
8000
10000
12000
data A fit A data B fit B
Cou
nts
Channel
100 150 200 2500
2000
4000
6000
8000
10000
12000
ArO
data B fit B Al Ti Si
Cou
nts
Channel
as-deposited sample
100 150 200 2500
2000
4000
6000
8000
10000
12000
14000
data A fit A data B fit B
Cou
nts
Channel
100 150 200 2500
2000
4000
6000
8000
10000
12000
14000
ArON
data fit Al Ti Si
Cou
nts
Channel
sample implanted to 2x1017 N/cm2
0 200 400 600 800 1000 1200 1400 1600 1800 20000
10
20
30
40
50
60
70
80
90
100
Al Ti Si Ar O NC
once
ntra
tion
(at%
)
Depth (1015
at/cm2)
0 200 400 600 800 1000 1200 1400 1600 1800 20000
20
40
60
80
100
Al Ti Si Ar O N
Con
cent
ratio
n (a
t%)
Depth (1015
at/cm2)
0 200 400 600 800 1000 1200 1400 1600 1800 20000
20
40
60
80
100
Al Ti Si Ar O
Con
cent
ratio
n (a
t%)
Depth (1015
at/cm2)
RBS depth profiles
as deposited
1x1017 N/cm2
2x1017 N/cm2
0 20 40 60 80 100 1200
20
40
60
80
100
Al Ti N O C SiC
once
ntra
tion
(at%
)
Sputtring time (min)
0 20 40 60 80 1000
20
40
60
80
100
Al Ti N O C Si
Con
cent
ratio
n (a
t%)
Sputtring time (min)
AES depth profilesJS Institute
as deposited
1x1017 N/cm2
2x1017 N/cm2
0 20 40 60 800
20
40
60
80
100
Al Ti O C Si
Con
cent
ratio
n (a
t%)
Sputtring time (min)
x-TEM analysis as-deposited samples
implanted to 2x1017 N/cm2
Conclusions for high fluence N implantation in Al/Ti multilayers
Nitrogen implantation can be used to form (Al,Ti)N multilayered structures from Al/Ti layers
The layers are intermixed => tightly bound at the interfaces, have graded composition, but the multilayered structure is preserved
Ion irradiation induces larger grains and formation of lamellar grains stretching over a number of layers
XPS studies are in progress to analyze chemical composition
Microhardness results – shown below
Comparative analysis of ion irradiation stability of Al/Ti versus AlN/TiN multilayers
Similar structures as described before, total thickness ~ 270 nm irradiated with 200 keV Ar+, from 5x1015 to 4x1016 ions/cm2
deposition of AlN/TiN done by reactive sputtering
700 800 900 1000 11000
2500
5000
7500
10000
as-deposited
1x1016
Ar/cm2
4x1016
Ar/cm2
Bac
ksca
tter
ing
yiel
d
Energy (keV)
RBS spectra of Al/Ti structures on Si (Surrey)as a function of Ar+ fluence
RBS analysis of Al/Ti sample irradiated with 200 keV Ar+, to 1x1016 ions/cm2
600 800 1000 12000
2500
5000
7500
10000
AlO Ar
TiSi
data fit
Bac
ksca
tter
ing
yiel
d
Energy (keV)
400 600 800 1000 12000
2000
4000
6000
8000
Si
Al
Ti
N
as-deposited
2x1016
Ar/cm2
B
acks
catt
erin
g yi
eld
Energy (keV)
RBS analysis of AlN/TiN structures on Si (Surrey)
as-deposited sample
100 200 3000
2000
4000
6000
8000
10000
12000
14000
data fit N Ti Si Al
Cou
nts
Channel
Titanium point by point depth profiles
0 250 500 750 1000 1250 1500 17500
20
40
60
80
100
as deposited
1 x 1016
Ar/cm2
2 x 1016
Ar/cm2
Con
cent
ratio
n (a
t.%
)
Depth (1015
at/cm2)
0 500 1000 1500 2000 25000
10
20
30
40
50
60
70
Titanium depth profiles
as deposited
1 x 1016
Ar/cm2
2 x 1016
Ar/cm2
Co
nce
ntr
atio
n (
at.%
)
Depth ( x 1015
at/cm2)
Al/Ti structureAlN/TiN structure
Interface mixing in Al/Ti system
200 400 600 800 1000 1200 1400 16000
10
20
30
40
50
60
Mix
ed t
hick
ness
(10
15 a
t/cm
2 )
Depth (1015
at/cm2)
1x1016
Ar/cm2
2x1016
Ar/cm2
Projected ion range
TEM analysis of Al/Ti multilayers
as-deposited implanted to 2x1016 ions/cm2
TEM analysis of AlN/TiN multilayersas-deposited
implanted to 2x1016 ions/cm2
implanted to 4x1016 ions/cm2
Other TEM images of AlN/TiN multilayers
as-deposited
implanted to 2x1016 ions/cm2
implanted to 4x1016 ions/cm2
2
0
1
3D d
balld
F Rk
NE
Ion Beam Mixing models fo diffusio profiles:
- Ballistic mixing:
k = Δσ2 /Φ
- Global spike mixing:
coh
r
coh
Dgb H
Hk
H
FNkk 2
2
3/51 1
- Local spike mixing:
1.5' '1 24/3 5/3
5(1 )
6t r
ls Dcoh coh
Z Hk k k F
N H H
ξ = [4mM/(mM)2]1/2 – kinematic factorm, M – masses of the ion and target atomΓo = 0.608 – dimensionless constant
N – atomic density of the targetRd 1nm – minimum separation
distance for the production of a stable Frenkel pairFD – deposited energy per ion per unit
length
k1=0.35 nm; k2=27.4 – constants
ΔHr – reaction enthalpy
ΔHcoh – cohesive energy of
the reaction products
k1’ and k2
’ – constants
Zt – atomic number of the target
Microhardness measurementsindentation depth ~ 200 nm
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
2x1017 ions/cm2
Mic
roh
ard
ne
ss (
N/m
m2)
TiN (9594 N/mm2)
as deposited
1x1017 ions/cm2
0,0 1x1016 2x1016 3x1016 4x1016
5000
6000
7000
8000
9000
10000
Mic
roh
ard
ne
ss (
N/m
m2 )
Ion fluence (ions/cm2)
Al/Ti AlN/TiN
TiN
Al/Ti Implanted with NAlN/TiN and Al/Ti implantedwith Ar
A.Misra, M.J.Demkowicz, X.Zhang, and R.G.Hoagland, JOM, Sep 2007, 62-65T. Höchbauer, A. Misra,a K. Hattar, and R. G. Hoagland, JAP, 98, (2005) 123516Los Alamos National Laboratory
(33-150 keV helium, 1 × 10^17/cm^2)
Cu/Nb irradiatedwith high fluence He+,
Effects of swift heavy ion irradiation and thermal annealing on nearlyimmiscible W/Ni multilayer structureSharmistha Bagchi , Satish Potdar, F. Singh, N. P. Lallaa (India)JAP, 102, (2007) 074310
W/Ni with 120 MeV Au9+,
as-deposited
and 5x1013 ions/cm 2
Conclusions for ion irradiation stability of Al/Ti versus AlN/TiN multilayers
Both systems preserve multilayered structure
Al and Ti are chemically reactive => the layers become progressively intermixed with increasing the ion fluence, formation of Al-Ti phases is detected; ion irradiation induces larger grains and formation of lamellar columns stretching over a number of layers
In AlN/TiN system the components are immiscible => no detectable intermixing is observed, it is lower compared even to ballistic mixing, only a small increase of the mean grain size in individual layers can be seen
Non-mixing, or de-mixing published so far only for immiscible metal layers Cu/Nb with He+, W/Ni with Au9+,
Presentations and publications:
two at IBMM-2006, five at YUKOMAT 2006 and 2007, two at ECAART-9 2007, one at IBA 2007
three journal papers and three accepted for NIM B
two papers submitted
2 Msci and 1 PhD thesis
Joint UniS – Vinča Workshop on Ion Beam Applications for MaterialsModification and Analysis – held in Vinča, Belgrade, 2nd September 2006, with 6 lecturers from Surrey, 2 from Germany, 1 from Hungary and 3 from Serbia, and a wide audience of local potential users
Further work will be on investigations of multilayered structuresprepared AlN/Al, TiN/Ti and Ta/Ti for further studies