1 / 21

Adam Kueltzo Thornton Fractional North High School July 30 th , 2009 University of Illinois at Chicago Advanced Material

Atomic Layer Deposited HfTiOx composite film On Si (100) with Al 2 O 3 as buffer layer . Adam Kueltzo Thornton Fractional North High School July 30 th , 2009 University of Illinois at Chicago Advanced Materials Research Laboratory (AMReL) Mentors: Dr. G. Jursich and Dr. C.G. Takoudis

rosaline
Download Presentation

Adam Kueltzo Thornton Fractional North High School July 30 th , 2009 University of Illinois at Chicago Advanced Material

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Atomic Layer Deposited HfTiOx composite film On Si (100) with Al2O3 as buffer layer Adam Kueltzo Thornton Fractional North High School July 30th, 2009 University of Illinois at Chicago Advanced Materials Research Laboratory (AMReL) Mentors: Dr. G. Jursich and Dr. C.G. Takoudis Departments of Bioengineering and Chemical Engineering

  2. Motivation for Research • An Al2O3 buffer layer is applied to improve the quality of the interfacial layer between high-k films (TiO2 and HfO2) and Si substrate • To run experiments in the atomic layer deposition (ALD) reactor and to examine thin film growth rates • To analyze the resulting thin films on silicon using spectral ellipsometry, Fourier Transform Infrared (FTIR) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and Atomic Force Microscopy (AFM).

  3. Hypotheses • A self-limiting reaction between a titanium, hafnium, and aluminum precursor, an oxidizer (H2O), and the silicon substrate • Good film uniformity on the substrate and film thickness control (using a spectral ellipsometer) • Absence of organic compounds in the resulting film structures (using FTIR spectroscopy) • Stoichiometry of the high-k material and the bonding states of the elements (using XP Spectroscopy)

  4. New High-k Dielectric Materials • The past few summers work has been conducted with Hafnium and recently Titanium and Aluminum • Hafnium oxide has a k value of 20-25 • Titanium oxide has a k value higher than 30 C = k  A t "High-k" stands for high dielectric constant, a measure of how much charge a material can hold.

  5. Why deposit multiple precursors on substrate? • Enhances dielectric constant (k) • Aids in the size miniaturization of semiconductor devices

  6. Atomic Layer Deposition (ALD) • Uses pulses of gaseous reactants (precursor and oxidizer) alternately fed into the reactor • Allows for atomic layer thickness control • Film thickness depends on number of deposition cycles

  7. ALD Process • “One Cycle” • Precursor • Purge (N2) • Oxidizer (H2O) • Purge (N2) http://www.cambridgenanotech.com/

  8. ALD Reactor Set-up Modification-capacity of three metal precursor deposition compared with previous two Ice bath Hot wall reactor Detailed on next slide C Operating Pressure = 0.2-1.5 Torr Moisture pulse = 0.05 s

  9. To ALD Reactor Female Elbow (VCR) Female Elbow (VCR) Union Tee (VCR) Ti precursor vessel (existing) Al precursor vessel (added)

  10. Acceptable Temperature Window • ALD reactions usually occur between 200-400 °C in the reactor • Above 400 °C, the chemical bonds are not stable and the precursor may decompose • Below 200 °C, the reaction rate may be reduced 200°C 400°C www.icknowledge.com/misc_technology/Atomic%20Layer%20Deposition%20Briefing.pdf

  11. Properties of the Precursors TDEAT Tetrakis(diethylamido)titaniumC16H40N4Ti -Molecular weight 336.42 g/mol -Appearance Clear orange liquid -Melting point < -20°C -Vapor pressure 0.5 torr at 90°C -Density 0.92 at 33°C -Viscosity 8.8 cSt at 34°C www.praxair.com

  12. TDEAH • Tetrakis(diethylamino)hafnium Hf(N(CH2CH3)2)4 • Molecular weight 467.0 g/mol • Appearance Pale yellow liquid • Melting point -68°C • Vapor pressure 0.2 torr at 90°C • Density 1.25 g/mL at 32°C • Viscosity 5.7 cSt at 30°C www.praxair.com

  13. TDEAA • Tris(diethylamino)aluminiumAl(N(C2H5)2)3 -Molecular Weight 486.7 g.mol-1 - Physical State Low MP solid - Melting Point 28-31°C - Boiling Point 250°C - Vapor Pressure 0.2 Torr @ 100°C - Density 0.915 g.cm-3 @ 25°C www.aloha.airliquide.com

  14. Reactor Temperature ~ 200oC Operating pressure .2-1.5 Torr Precursor Temperatures (Hf 67oC) (Ti 62oC) (Al 100oC) Purge Gas (N) Purge time after precursor pulses - 10 seconds Purge time after oxidizer (H2O) pulse – 20 seconds kept at 0oC to stabilize vapor pressure Experimental Conditions

  15. Reaction temperature: 200oC Plugs number : 5

  16. Future Work • Further validate the deposition rate of TDEAA - Thickness determination • Deposition of TDEAH and TDEAT • Apply TDEAA buffer layer to silicon substrate

  17. References Anthony, J.M., Wallace, R.M., & Wilk, G.D. (2001). High-k Gate Dielectrics: Current Status and Materials Properties Considerations. Applied Physics Review, 89 , 5243-5275. Brain, Marshall. (n.d.). How Semiconductors Work. [WWW page]. http://computer.howstuffworks.com/diode.htm. Cambridge NanoTech, Inc. (2003-2007). Cambridge NanoTech: Atomic Layer Deposition Systems. [WWWpage]. http://www.cambridgenanotech.com/. IC Knowledge LLC. (2004). Technology Backgrounder: Atomic Layer Deposition. [WWWpage]. http://www.icknowledge.com/misc_technology/Atomic%20Layer%20Deposition%20 Briefing.pdf. Intel® Education. (n.d.) Inside The Intel® Manufacturing Process: How Transistors Work. [WWWpage]. http://www.intel.com/education/transworks/index.htm. Majumder, P., Jursich, G., Kueltzo, A., & Takoudis, C. (2008). Atomic Layer Deposition of Y2O3 Films on Silicon Using Tris(ethylcyclopentadienyl) Yttrium Precursor and Water Vapor. Journal of The Electrochemical Society. 155(8), G152-G158. Mutschler, Ann Steffora. (2007). Intel, IBM Embrace High-k Gates for 45nm. Electronic News. Peters, Laura. (2007). Behind the Breakdown of High-k Dielectrics.Semiconductor International. p. 30. Praxair Technology, Inc. [WWWpage]. http://www.praxair.com Zant, P. V. (2000). Microchip Fabrication (4th ed.). New York: McGraw Hill. Air Liquide[WWWpage]. http://www.airliquide.com/en/semiconductors/aloha-advanced-precursors/high-k.html

  18. Acknowledgements • EEC-NSF Grant #0926260 • Mentors: Dr. Greg Jursich and Dr. Christos Takoudis • Doctoral students: Qian Tao and Manish Singh

More Related