Microchip-Embedded Capacitors for Implantable Neural Stimulators

  • Orlando Auciello
Part of the Biological and Medical Physics, Biomedical Engineering book series (BIOMEDICAL)


Miniaturization of microchips for implantation in the human body (e.g., microchip for the artificial retina to restore sight to people blinded by retina photoreceptors degeneration) requires the integration of high-capacitance (≥ 10 μF) energy-storage capacitors into the microchip. These capacitors would be based on high-dielectric constant layers, preferably made of materials that are bioinert (not affected by human body fluids) and are biocompatible (do not elicit adverse reactions in the human body). This chapter focuses on reviewing the work being done at Argonne National Laboratory (Materials Science Division and Center for Nanoscale Materials) to develop high-capacitance microchip-embedded capacitors based on novel high-K dielectric layers (TiAlOx or TiO2/Al2O3 superlattices). The microchip-embedded capacitor provides energy storage and electromagnetic signal coupling needed for neural stimulations. Advances in neural prostheses such as artificial retinas and cochlear implants require miniaturization of device size to minimize tissue damage and improve device/tissue interfaces in the human body. Therefore, development of microchip-embedded capacitors is critical to achieve full-implantable biomedical device miniaturization.


Atomic Layer Deposition Cochlear Implant High Dielectric Constant Gate Oxide Important Electronic Device 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The author wishes to acknowledge support from the U. S. Department of Energy, BES-Materials Science for work in the Materials Science Division, under contract W-31-109-ENG-38. The work at the Center for Nanoscale Materials and at the Electron Microscopy Center for Materials Research at Argonne National Laboratory was supported by the U.S. Department of Energy-Office of Science under Contract No. DE-AC02-06CH11357 by U Chicago Argonne, LLC. The author also acknowledges the many colleagues and postdoctorals who have made substantial contributions to the work discussed in this chapter over the years, namely: J.A. Carlisle, W. Fan, B. Kabius, R. Baragiola, and E.A. Irene.


  1. 1.
    Robertson J (2004) High dielectric constant oxides. Eur Phys J Appl Phys 28:265.CrossRefGoogle Scholar
  2. 2.
    Robertson J (2006) High dielectric constant gate oxides for metal oxide Si transistors. Rep Prog Phys 69: 327.CrossRefGoogle Scholar
  3. 3.
    Wilk G, Wallace RM, Anthony JM (2001) High-gate dielectrics: Current status and materials properties considerations. J Appl Phys 89:5243.CrossRefGoogle Scholar
  4. 4.
    Wallace RM, Wilk GD (2003) High-κ dielectric materials for microelectronics. Crit Rev Solid State Mater Sci 28:231.CrossRefGoogle Scholar
  5. 5.
    Wallace RM, High dielectric constant gate oxides (private communication).Google Scholar
  6. 6.
    Huff H, Gilmer D (eds) (2004) High K Gate Dielectrics. Berlin: Springer.Google Scholar
  7. 7.
    Houssa M (ed) (2003) High Dielectric Constant Materials: VLSI MOSFET Applications. London: IOP.Google Scholar
  8. 8.
    Demkov AA, Navrotsky A (eds) (2005) Materials Fundamentals of Gate Oxides. Dordrecht: Springer.Google Scholar
  9. 9.
    Sugizaki T, Kohayashi M, Ishidao M et al. (2003) Novel Multi-bit SONOS Type Flash Memory Using a High-k Charge Trapping Layer. Symposium on VLSl Technology Digest of Technical Papers, p. 27.Google Scholar
  10. 10.
    Sim H, Samantaray CB, Lee T et al. (2004) Electrical and structural characteristics of high-k gate dielectrics with epitaxial Si3N4 interfacial layer on Si(111). Jpn J Appl Phys Part 1 43(12):7926.CrossRefGoogle Scholar
  11. 11.
    Klein TM, Niu D, Epling WS et al. (1999) Evidence of aluminum silicate formation during chemical vapor deposition of amorphous Al2O3 thin films on Si(100). Appl Phys Lett 75:4001.CrossRefGoogle Scholar
  12. 12.
    Gusev EP, Copel M, Cartier E et al. (2000) High-resolution depth profiling in ultrathin Al2O3 films on Si. Appl Phys Lett. 76(2):176.CrossRefGoogle Scholar
  13. 13.
    Chin A, Wu YH, Chen SB et al. (2000) High quality La2O3 and Al2O3 gate dielectrics with equivalent oxide thickness 5–10 Å. Tech Dig VLSI Symp, p. 16.Google Scholar
  14. 14.
    Roy PK, Kizilyalli IC (1998) Stacked high-gate dielectric for gigascale integration of metal–oxide–semiconductor technologies. Appl Phys Lett 72:2835.CrossRefGoogle Scholar
  15. 15.
    Lu Q, Park D, Kalnitsky A et al. (1998) Leakage current comparison between ultrathin Ta2O5 films and conventional gate dielectrics. IEEE Electron Device Lett 19:341.CrossRefGoogle Scholar
  16. 16.
    Fleming RM, Lang DV, Jones CDW et al. (2000) Defect dominated charge transport in amorphous Ta2O5 thin films. J Appl Phys 88:850.CrossRefGoogle Scholar
  17. 17.
    Kadoshima M, Hratani M, Shimamoto Y et al. (2003) Rutile-type TiO2 thin film for high-k gate insulator. Thin Solid Films 424(2):224.CrossRefGoogle Scholar
  18. 18.
    Bera MK, Maiti CK (2007) Charge trapping properties of ultra-thin TiO2 films on strained-Si. Semicond Sci Technol 22:774.CrossRefGoogle Scholar
  19. 19.
    Yu Z, Ramdani J, Curless JA et al. (2000) Epitaxial oxide thin films on Si (001). J Vac Sci Technol B 18:2139.CrossRefGoogle Scholar
  20. 20.
    McKee RA, Walker FJ, Chisholm MF (1998) Crystalline oxides on silicon: The first five monolayers. Phys Rev Lett 81:3014.CrossRefGoogle Scholar
  21. 21.
    Robertson J, Xiong K, Falabretti B (2005) Point defects in ZrO2 high K gate oxide. IEEE Trans Device Mater Reliab 5(1):84.CrossRefGoogle Scholar
  22. 22.
    Huang AP, Fu RKY, Chu PK et al. (2005) Plasma nitridation and microstructure of high-k ZrO2 thin films fabricated by cathodic arc deposition. J Crys Growth 277:422.CrossRefGoogle Scholar
  23. 23.
    Nishikawa T, Otsuka T, Morita K (2002) Reduction of leakage current by HfO2 high K dielectric film stacked on the ferroelectric layer of a MFIS structure. Integr Ferroelectr 48(1):41.CrossRefGoogle Scholar
  24. 24.
    Chatterjee S, Kuo Y, Lu J et al. (2006) Electrical reliability aspects of HfO2 high-k gate dielectrics with TaN metal gate electrodes under constant voltage stress. Microelectron Reliab 46(1):69.CrossRefGoogle Scholar
  25. 25.
    Aoyama T, Sugita Y, Morisaki Y et al. (2002) CMOSFETs using HfO2 High-k gate dielectrics. Proc Symp Semicond Integr Circ Technol 63:6.Google Scholar
  26. 26.
    Iwai H et al. (2002) Advanced gate dielectric materials for sub-100 nm CMOS. Tech Digest Int Electron Devices Meeting (IEEE).Google Scholar
  27. 27.
    Busani T, Devine RA (2005) The importance of network structure in high-K dielectrics: LaAlO3, Pr2O3, and Ta2O5. J Appl Phys 98:044102.CrossRefGoogle Scholar
  28. 28.
    Shao QY, Li AD, Cheng JB et al. (2005) Growth behavior of high k LaAlO3 films on Si by metalorganic chemical vapor deposition for alternative gate dielectric application. Appl Surf Sci 250(1)4:14.CrossRefGoogle Scholar
  29. 29.
    Robertson J (2000) Band offsets of wide-band-gap oxides and implications for future electronic devices. J Vac Sci Technol B 18:1785–1791.CrossRefGoogle Scholar
  30. 30.
    Osburn CM, Kim I, Han SK et al. (2002) Vertically scaled MOSFET gate stacks and junctions: How far are we likely to go? IBM J Res Dev 46:299.CrossRefGoogle Scholar
  31. 31.
    Auciello O, Fan W, Kabius B et al. (2005) New TiAl alloy high-K dielectric layer for next generation integrated circuit gates. Appl Phys Lett 86:1.CrossRefGoogle Scholar
  32. 32.
    Tripp MK, Fabreguette F, Herrmann CF et al. (2005) Multilayer coating method for x-ray reflectivity enhancement of polysilicon micro-mirrors at 1.54 Å wavelength, Micromachining Technology for Micro-Optics and Nano-Optics III. Johnson EG, Nordin GP, Suleski TJ (eds) Proceedings of SPIE Vol. 5720 (SPIE), Bellingham, WA, 241.Google Scholar
  33. 33.
    Dillon AC, Ott AW, George SM et al. (1995) Surface chemistry of Al2O3 deposition using Al(CH3)3 and H2O in a binary reaction sequence. Surf Sci 322:230.CrossRefGoogle Scholar
  34. 34.
    Lakomaa EL, Haukka S, Suntola S (1992) Atomic layer growth of TiO2 on silica. Appl Surf Sci 60/61:742.CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  1. 1.Materials Science DivisionArgonne National LaboratoryArgonneUSA
  2. 2.Center for Nanoscale MaterialsArgonneUSA

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