selective atomic layer deposition of tio 2 on silicon/copper- patterned substrates uic reu 2011...
TRANSCRIPT
![Page 1: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/1.jpg)
Selective Atomic Layer Deposition of TiO2 on Silicon/Copper-
patterned Substrates
UIC REU 2011
AMReL, University of Illinois at Chicago
Abigail JablanskyDepartment of Chemical and Biomolecular Engineering,
University of Pennsylvania
![Page 2: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/2.jpg)
What is ALD?• Atomic layer deposition• Method:
– Precursor (TDEAT)– Purge (N2)– Oxidant (H2O)– Purge (N2)
• Batch adsorption process• Easily controlled but
time-consuming• Characterized with ellipsometry,
X-ray photoelectron spectroscopy(XPS)
• Diverse applicationswww.cambridgenanotech.com/ald
![Page 3: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/3.jpg)
Copper and Silicon
• Conductive substrate• Small channels of
conduction in microelectronics
• Need a thin barrier layer on silicon
• Copper oxidizes more easily– Selective ALD (SALD)– Native oxide
www.electroiq.com
![Page 4: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/4.jpg)
Native Oxides• Prevention
– Self-assemblingmolecules1
• Minimization– Limited air exposure2
– Few cycles3
• Reduction– GaAs oxide remains under
HfO2 but converted under Al2O3
4
Tao, Q.; Jursich, G.; Takoudis, C. App. Phys. Lett. 2010, 96, 192105
1Chen, R.; Kim, H.; McIntyre, P.C.; Bent, S.F. Chem. Mater. 2005, 17, 536.2Lee, H.D.; Feng, T.; Yu, L.; Mastrogiovanni, D.; Wan, A.; Gustafsson, T.; Garfunkel, E. App. Phys. Lett. 2009, 94, 222108.3Tao, Q.; Overhage, K.; Jursich, G.; Takoudis, C. Submitted to Journal of Physi Chem. C. 2011.4Frank, M.M.; Wilk, G.D.; Starodub, D.; Gustafsson, T.; Garfunkel, E.; Chabal, Y.J.; Grazul, J.; Muller, D.A. App. Phys. Lett. 2005, 86, 152904.
![Page 5: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/5.jpg)
Copper Oxides
• Cu2O (cuprous oxide)– Linear– Most stable copper
compounds at high T
– Forms ammine under NH3
5
• CuO (cupric oxide)– Square planar– Decomposes at
high T to Cu2O + O2
– H2 or CO reduction at 250oC5• Cu2O forms first, then CuO if stable6
• Reduction methods
5Cotton, F.A.; Wilkinson, G. Advanced Inorganic Chemistry, 2nd ed. New York: Interscience Publishers, 1966, pp.894-902.6Zhu, Y.; Mimura, K.; Lim, J.; Isshiki, M.; Jiang, Q. Metal. and Mineral Trans. A. 2006, 37A, 1231.
![Page 6: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/6.jpg)
Project Description
• ALD of TiO2 onto Si/Cu wafers– Precursor: tetrakis(diethylamino)titanium (TDEAT)– Oxidizer: water
• Compare 24-hr Cu (1 nm native oxide) exposure to 1-hr7
• Minimize exposure from reactor to ellipsometer, x-ray photoelectron spectroscopy (XPS)
7Tao, Q. PhD Dissertation, University of Illinois at Chicago, 2011.
![Page 7: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/7.jpg)
Reactor Schematic
Ice bath
Hot wall reactor
Tao, Q. PhD Dissertation, University of Illinois at Chicago, 2011.
![Page 8: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/8.jpg)
Experimental Setup
![Page 9: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/9.jpg)
Characterization
Ellipsometry
• Reflects light off thin films• Measures polarization
after reflection
X-ray photoelectron spectroscopy (XPS)
• X-rays are energy source• Measures kinetic energy,
number of escaping electrons
![Page 10: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/10.jpg)
Results• Verified Tao’s work7
– Constant growth rate = linear growth
0 5 10 15 20 25 30 350
5
10
15
20
25
30
f(x) = 0.858713450292395 xR² = 0.956743860444266
Thickness of TiO2 on Si
Number of cycles
Th
ickn
ess
(A)
7Tao, Q. PhD Dissertation, University of Illinois at Chicago, 2011.
![Page 11: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/11.jpg)
Troubleshooting• Temperature
– Increases along path to reactor– Keep oxidizer cold
• Pressure– “Resting pressure” around 0.176 torr– Cycles during deposition
• N2 tank, H2O level in bubbler
• Check ellipsometer• Precursor level, clogged pipes
![Page 12: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/12.jpg)
Results (cont.)
The colors could represent a deposition layer thickness profile or a chemical vapor deposition (CVD).
![Page 13: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/13.jpg)
Summary
• Objective: SALD of TiO2 on Si for microelectronic applications
• Method: reduce native oxide on Cu– Minimize air exposure (in progress)– In situ reduction (future work)
• Characterization: ellipsometry, XPS• Results to date verify prior research• Not enough data to conclude about TiO2 on copper
• Troubleshooting, design setbacks are important parts of engineering
![Page 14: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/14.jpg)
Acknowledgements
• National Science Foundation, EEC-NSF Grant # 1062943
• CMMI-NSF Grant # 1134753• Jorge I. Rossero A.• Runshen Xu• Arman Butt• Dr. Jursich• Dr. Takoudis
![Page 15: Selective Atomic Layer Deposition of TiO 2 on Silicon/Copper- patterned Substrates UIC REU 2011 AMReL, University of Illinois at Chicago Abigail Jablansky](https://reader035.vdocuments.mx/reader035/viewer/2022062515/56649cbb5503460f949832a7/html5/thumbnails/15.jpg)
References
•Chen, R.; Kim, H.; McIntyre, P.C.; Bent, S.F. Chem. Mater. 2005, 17, 536.•Lee, H.D.; Feng, T.; Yu, L.; Mastrogiovanni, D.; Wan, A.; Gustafsson, T.; Garfunkel, E. App. Phys. Lett. 2009, 94, 222108.
•Tao, Q.; Jursich, G.; Takoudis, C. App. Phys. Lett. 2010, 96, 192105•Tao, Q.; Overhage, K.; Jursich, G.; Takoudis, C. Submitted to Journal of Phys. Chem. C. 2011.
•Frank, M.M.; Wilk, G.D.; Starodub, D.; Gustafsson, T.; Garfunkel, E.; Chabal, Y.J.; Grazul, J.; Muller, D.A. App. Phys. Lett. 2005, 86, 152904.
•Cotton, F.A.; Wilkinson, G. Advanced Inorganic Chemistry, 2nd ed. New York: Interscience Publishers, 1966, pp.894-902.
•Zhu, Y.; Mimura, K.; Lim, J.; Isshiki, M.; Jiang, Q. Metal. and Mineral Trans. A. 2006, 37A, 1231.
•Tao, Q. PhD Dissertation, University of Illinois at Chicago, 2011.•Falkenstein, Z.; Hakovirta, M.; Nastasi, M. Thin Solid Films. 2001, 381, 84.•Tompkins, H.G.; Allara, D.L. J. Colloid and Interface Science. 1974, 49, 410.•Sakata, Y.; Domen, K.; Maruya, K.-I.; Onishi, T. Appl. Spec. 1988, 42, 442.