ald of manganese silicate - faculty.chemistry.harvard.edu
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ALD of Manganese Silicate
Roy G. Gordon,1,2* Lu Sun,2 Qiang Chen,3 Jin-Seong Park4
and Sang Bok Kim1
1Department of Chemistry and Chemical Biology2School of Engineering and Applied Sciences
Harvard University, Cambridge, MA, USA3Beijing Institute of Graphic Communication, Beijing, China
4Hanyang University, Seoul, Korea
*Email: [email protected]
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Outline
2
Potential Applications of Manganese Silicate
ALD Process for Manganese Oxide, MnO
ALD Process for Manganese Silicate
Properties of Manganese Silicate
2222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222222
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Potential Applications of MnSixOy
barrier to diffusion of copper, water and oxygenadhesion promoter between copper and insulators nucleating layer for vapor deposition of copper
3
Copper wires in computer chips could use MnSixOy as a
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Manganese Precursors
4
N
NN
N
MnN N
NNMn
manganese(II) bis(N,N’-diisopropylpentamidinate)
manganese(II) bis(N,N’-di-tert-butylacetamidinate)
melting point: 60 °Cboiling point: 120 °C / 0.02 torr
melting point: 107 °Cboiling point: 100 °C/ 0.07 torr
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Saturation Curve for Manganese Oxide
5
0 4 8 12 16 20 24 280.0
0.2
0.4
0.6
0.8
1.0
1.2Th
ickn
ess p
er cy
cle (
A/cy
cle)
Mn-ipr ( mole/cycle)
200oC
N
NN
N
Mn
Saturated for doses > 10-5 moles/cycle
Co-reactant: water
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0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 5 10 15 20 250.0
0.2
0.4
0.6
0.8
1.0
Ref
ract
ive I
ndex
Refractive IndexThic
knes
s per
cycl
e (A
/cyc
le)
mole/cycle (10-6 mole/cycle)
Growth rate @ 200oC/85oC or 95oC
6
Saturation Curve for Manganese OxideSaturated for doses > 10-5 moles/cycle
N N
NNMn
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Thickness per Cycle for Manganese Oxide
200 240 280 320 3600.0
0.2
0.4
0.6
0.8
1.0
0.0
0.5
1.0
1.5
2.0
2.5
Thick
ness
per
cycle
(A/c
ycle)
Deposition temperature
growth rate# of cycle = 100095oC*3, H2O*2
Ref
racti
ve In
dex
Refractive Index
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N
NN
N
Mn
nearly constant from 200 to 340 oC
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0 200 400 600 800 1000
A.U.
Channel (eV)
Data Simulation
Rutherford Backscattering Spectroscopy
Mn
O
Csubstrate
=> Stoichiometry MnO Adding O2 cycles => MnO2
8
Co-reactant: water
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0 200 400 600 800 1000
Mn 2p3
O 1s
Inten
sity (
A.U.
)
Binding Energy (eV)
Mn (2p3) : 641.9 eV O (1s) : 530.9 eV carbon-free : about 285 eV(after sputtering 1 min)
X-Ray Photoelectron Spectroscopy
9
< 1% C or N impurities
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XRD shows polycrystalline MnO
20 30 40 50 60
MnO(220)MnO(200)
Inten
sity
(A. U
.)
2
250oC MnOCubic structure
MnO(111)
10
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Precursors for Silicon and Oxygen
11
Si O
O
O
O
H
Si O
O
O
O
H
tris-tert-butoxysilanol (TBS) tris-tert-pentoxysilanol (TPS)
melting point: 63 - 65 °Cboiling point: 205 - 210 °C/ 760 torr
melting point: < 20 °Cboiling point: 96-99 °C/ 2-3 torr
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0 10 20 30 40 500
5
10
15
20
thic
knes
s (n
m)
cycles
ALD Conditions for Manganese Silicate
12
Substrate: SiO2/SiUV ozone cleaning: 2 minDrying at 350°C: 1 hour
Mn amidinate source =105°CSi/O source (TPS)=120°C
T(substrate)= 350°C
Cycle times (s): 1/30/4/30 (Mn(amd)/purge/TPS/purge)
growth per cycle = 0.43 nm
High growth per cycle due to a catalytic mechanism similar to that of aluminum-catalyzed silica: Dennis Hausmann, Jill Becker, ShenglongWang, Roy G. Gordon, Science 298, 402 (2002)
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Saturation Curve for MnSixOy vs. Silicate Precursor
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0 2 4 6 8 10 12 14 16 18
0.30
0.35
0.40
0.45
0.50
0.55G
rowt
h ra
te (n
m/c
ycle
)
TPS doses
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Composition by Rutherford Backscattering Spectroscopy
16
Cycles Mn1015at/cm^2
Si 1015at/cm^2
O1015at/cm^2 Mn:Si:O
10 2.32 6.2 24 1 : 2.7 : 10
20 5.56 15 47 1 : 2.7 : 8
50 15.4 41 117 1 : 2.7 : 7.6
Stoichiometry ~ MnSi2.7O7.6 so Mn is oxidized to Mn4+
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Cu diffusion test
SiO22
Si
SiOCu 200 nm
8 nm10 nm
SiO22
Si
SiOMnSixOy
200 nm
8 nm
M Si O
Cu
visible appearance
anneal samples in N2 for 1h at 450 C, use Ni etchant to remove Cu film, then EDX
17
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CV tests after electric field at room temperature
10V for 1min
12V for 1min
15V for 1min
10V for 1min
12V for 1min
15V for 1min
15 nm
SiO22
Si
SiOMnSixOy
200 nm
60 nm
M Si O
Cu
SiO22
Si
SiOCu 200 nm
60 nm
18
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Effectiveness of MnSixOy as a Cu Diffusion Barrier
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Composition Structure Cu Barrier Diffusion PathwaySiO2 amorphous no open tetrahedral network
MnSi2.7O7.6 amorphous yes paths blocked by Mn ions
MnO polycrystalline no grain boundaries
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Acknowledgements
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Precursors supplied by Dow Chemical, Sigma-Aldrich and Strem Chemical
The work was supported as part of the Center for the Next Generation of Materials by Design, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science
Facilities at Harvard’s Center for Nanoscale Systems (CNS), a member of the National Nanotechnology Infrastructure Network (NNIN), previously supported by the U. S. National Science Foundation