Journal of the Institute of Electronics Engineers of Korea SD (대한전자공학회논문지SD)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지

Electrical and Chemical Stability of Mo Gate Electrode for PMOS

PMOS에 적합한 Mo 전극의 전기적 화학적 안정성

  • 노영진 (한국항공대학교 전자·정보통신·컴퓨터공학부) ;
  • 이충근 (한국항공대학교 전자·정보통신·컴퓨터공학) ;
  • 홍신남 (한국항공대학교 전자·정보통신·컴퓨터공학부)
  • Published : 2004.04.01
Download PDF
⟨ Previous Next ⟩

Abstract

In this paper, the properties of Mo as PMOS gate electrodes were studied. The work-function of Mo extracted from C-V characteristic curves was appropriate for PMOS. To identify the electrical and chemical stability of Mo metal gate, the changes of work-function and EOT(Effective Oxide Thickness) values were investigated after 600, 700, 800 and 90$0^{\circ}C$ RTA(Rapid Thermal Annealing). Also it was found that Mo metal gate was stable up to 90$0^{\circ}C$ with underlying SiO$_2$through X-ray diffraction measurement. Sheet resistances of Mo metal gate obtained from 4-point probe were less than 10$\Omega$/$\square$ that was much lower than those of polysilicon.

본 논문에서는 Mo을 PMOS의 금속 게이트로 사용하였을 때의 Mo의 특성에 대해서 연구 하였다. Mo을 게이트 물질로 사용한 MOS 커패시터를 제작하였고, 소자의 C-V 특성 곡선으로부터 일함수를 추출하였다. 그 결과 Mo 게이트는 PMOS에 적합한 일함수를 나타내는 것을 알 수 있었다. Mo의 전기적/화학적 안정성을 검증하기 위해서 600, 700, 800 그리고 900℃에서 급속 열처리를 수행하였으며 열처리 이후 유효 산화막의 두께와 일함수의 변화를 살펴보았다. 또한 900℃ 열처리 이후의 XRD 분석을 통해서 Mo 금속 게이트가 SiO₂에 대해서 안정하다는 것을 확인하였다. 4점 탐침기로 측정한 Mo 금속 게이트의 면저항은 10Ω/□ 미만으로 폴리 실리콘에 비해서 매우 작은 값을 나타냈다.

Keywords

References

  1. H. Zhong, S. N. Hong, Y. S. Suh, H. Lazar, G. Heuss and V. Misra, 'Propertied of Ru-Ta alloys as gate electrodes for NMOS and PMOS silic on devices', IEDM 01, p. 467, 2001 https://doi.org/10.1109/IEDM.2001.979543
  2. H. Iwai, S. I. Ohmi, 'Problems and solutions for downsizing CMOS below $0.1{\mu}m$', ICE2000 Proc., p. 1, 2000 https://doi.org/10.1109/SMELEC.2000.932298
  3. J. R. Hauser et al, 'SRC working paper', 1997
  4. C. H. Choi, P. R. Chidambaram, R. Khamankar, C. F. Machala, Z. Yu, R. W. Dutton, 'Dopant profile and gate geometric effects on polysilicon gate depletion in scaled MOS', IEEE Trans. on Electron Dev., vol. 49, no. 7, p. 1227, 2002 https://doi.org/10.1109/TED.2002.1013280
  5. V. Misra, G. P. Heuss, and H. Zhong 'Use of metal -oxide-semiconductor capacitors to detect interactions of Hf and Zr gate electrodes with SiO₂and ZrO2', Appl. Phys. Lett., vol. 78, no. 26, p. 4166, 2001 https://doi.org/10.1063/1.1380240
  6. R. Lin, Q. Lu, P. Ranade, T. J. King, and C. Hu, 'An adjustable work function technology using Mo gate for CMOS devies', IEEE Electron Device Lett., vol. 23, no. 1, p. 49, 2002 https://doi.org/10.1109/55.974809
  7. Q. Lu, Y. C. Yeo, P. Ranade, H. Takeuchi, R. J. King, and C. Hu, 'Dual-metal gate technology for deep-submicron CMOS transistors', Symposium on VLSI Technology Digest of Technical Paper, p. 72, 2000 https://doi.org/10.1109/VLSIT.2000.852774
  8. Y. S. Suh, G. Heuss, H. Zhong, S. N. Hong, and V. Misra, 'Electrical characteristics of TaSixNy gate electrodes', Symposium on VLSI Technology Digest of Technical Paper, p. 47, 2001 https://doi.org/10.1109/VLSIT.2001.934940
  9. M. A. Pawlak, T. Schram, K. Maex, A. Vantomme, 'Investigation of Iridium as a gate electrode for deep sub-micron CMOS technology', pbulished by Elsevier B.V. 2003
  10. T. Ushiki,K. Kawai, I. Ohshima and T. Ohmi, 'Chemical reaction concerns of gate metal with gate dielectric in Ta gate MOS device: An effect of self-sealing barrier configuration interposed between Ta and $Sio_2$', IEEE Trans. on Electron Dev., vol. 47, no. 11, p. 2201 https://doi.org/10.1109/16.877184
  11. Q. Lu, R. Lin, P. Ranade, T. J. King, C. Hu, 'Metal gate work function adjustment for future CMOS technology', Symposium on VLSI Technology Digest of Technical Paper, p. 45, 2001 https://doi.org/10.1109/VLSIT.2001.934939
  12. R. Beyers, 'Thermodynamic considerations in refractory metal-silicon-oxygen systems', J. Appl. Phys. vol. 56, no. 1, p. 147, 1984 https://doi.org/10.1063/1.333738
  13. I. Brain, 'Thermochemical data of pure substances', John Wiley and Sons, p. 1440, 1994
  14. D. R. Gaskell, 'Introduction to metallurgical thermodynamics', McGraw-Hill, p. 226, 1998
  15. H. Zhong, G. Heuss, and V. Misra, 'Characterization of RuO2 electrode on Zr silicate and ZrO2 dielectrics', Applied Physics Letters, vol. 78, no. 8, p. 1134, 2001 https://doi.org/10.1063/1.1347402
  16. J. E. Suarez, B. E. Johnson, and B. El-Karch, 'Thermal stability of polysilicon resistors, IEEE, p. 537, 1991 https://doi.org/10.1109/ECTC.1991.163929
  17. T. S. Kalkur, Y. C. Lu, 'Thermal properties of ruthenium dioxide films', Thin Solid Films, vol. 205, p. 266, 1991