The Transactions of the Korean Institute of Electrical Engineers C (대한전기학회논문지:전기물성ㆍ응용부문C)

The Korean Institute of Electrical Engineers (대한전기학회)
권호 표지

A Study on the Properties of WS $i_{x}$ Thin Film with Formation Conditions of Polycide

폴리사이드 형성 조건에 따른 WS $i_{x}$ 박막 특성에 관한 연구

  • 정양희 (여수대학 전기공학과) ;
  • 강성준 (여수대학 반도체ㆍ응용물리학과) ;
  • 김경원 (하이닉스반도체)
  • Published : 2003.09.01
Download PDF
⟨ Previous Next ⟩

Abstract

We perform the physical analysis such that Si/W composition ratios and phosphorus distribution change in the W/S $i_{x}$ thin films according to phosphorus concentration of polysilicon and W $F_{6}$ flow rate for the formation of WS $i_{x}$ polycide used as a gate electrode. We report that these physical characteristics have effects on the contact resistance between word line and bit line in DRAM devices. RBS measurements show that for the samples having phosphorus concentrations of 4.75 and 6.0${\times}$10$^{2-}$ atoms/㎤ in polysilicon, by applying W $F_{6}$ flow rates decreases from 4.5 to 3.5 sccm, Si/W composition ratio has increases to 2.05∼2.24 and 2.01∼2.19, respectively. SIMS analysis give that phosphorus concentration of polysilicon for both samples have decreases after annealing, but phosphorus concentration of WS $i_{x}$ thin film has increases by applying W $F_{6}$ flow rates decreases from 4.5 to 3.5 sccm. The contact resistance between word line and bit line in the sample with phosphorus concentration of 6.0 ${\times}$ 10$^{20}$ atoms/㎤ in polysilicon is lower than the sample with 4.75 ${\times}$ 10$^{20}$ atoms/㎤ After applying W $F_{6}$ flow rates decreases from 4.5 to 3.5 sccm, the contact resistance has been improved dramatically from 10.1 to 2.3 $\mu$ $\Omega$-$\textrm{cm}^2$.

Keywords

References

  1. K. Roh, S. Youn, S. Yang, and Roh, 'Tungsten silicide for alternate gate metal in metal-oxide-semiconductor devices', J. Vac. Sci. Technol., vol. 19, pp. 1562-1565, 2001 https://doi.org/10.1116/1.1345914
  2. Y. Shioya, S. Kawamura, et al., 'Effect of fluorine in chemical-vapor-deposited tungsten silicide film on electrical breakdown of $SiO_2$ film', J. Appl. Phys., vol. 61, pp. 5102-5109, 1987 https://doi.org/10.1063/1.338336
  3. P. J. Wright, M. Wong, and K. C. Saraswat, 'The effect of fluorine on gate dielectric properties', IEDM tech. Dig., pp. 574-577, 1987
  4. P. J. Wright and K. C. saraswat, 'The effect of fluorine in silicon dioxide gate dielectrics', IEEE Trans. Election Devices, vol. 36, pp. 879-889, 1989 https://doi.org/10.1109/16.299669
  5. H. J. Whitlow et al., 'Fluorine in low-pressure chemical vapor deposited W/Si contact structures: Inclusion and thermal stability', Appl. Phys. Lett., vol. 50, pp. 1497-1499, 1987 https://doi.org/10.1063/1.97811
  6. C. S. Yoo, T. H. Lin, and N. S. Tsai, 'Si/W changes and film peeling during polycide annealing', J. J. Appl. Phys., vol. 29, pp. 2535-2540, 1990 https://doi.org/10.1143/JJAP.29.2535
  7. T. Hara, T. Miyamoto, and T. Yokoyama, 'Tungsten silicide fims deposited by $SiH_2Cl_2-WF_6$ chemical reaction', J. Electrochem. Soc., vol. 136, pp. 1177-1180, 1989 https://doi.org/10.1149/1.2096848
  8. J. T. Hillman, W.M. Triggs, and M. Aruga, 'Characterization of $WSI_x$ fIms deposited by reacting $WF_6$ with a mixture of $SiH_2CI_2$ and $Si_2H_6$', J. Electrochem.Soc., vol. 139, pp. 3574-3578, 1992 https://doi.org/10.1149/1.2069124
  9. 정양희, 강성준, 강희순, 'DCS Post Flow 가 $WSi_x$ 박막 특성에 미치는 영향', 대한전기학회 논문지 C권, 52권 4호, pp. 173-178, 2003
  10. S. Santucci, L. Lozzi, M. Passacantando, et al., 'Studies on structural, electrical, compositional, and mechanical properties of $WSi_{x}$ thin fiIms produced by low-pressure chemical vapor deposition', J. Vac. Sci. Technol., vol. 16, pp. 1207-1212, 1998 https://doi.org/10.1116/1.581260
  11. J. S. Byun, B. H. Lee, J. S. Park,and J. J. Kim, 'Characterization of the dopant effect on dichlorosilane-based tungsten silicide deposition', J. Electrochem. Soc., vol. 144, pp. 3572-3582, 1997 https://doi.org/10.1149/1.1838050
  12. J. S. Byun, B. H. Lee, J. J. Kim, et al., 'Formation of high conductivity $WSi_x$ layer and its characterization as a gate electrode', J. Electrochem. Soc., vol. 145, pp. 3228-3235, 1998 https://doi.org/10.1149/1.1838790
  13. S. M. Sze, Semiconductor Devices, John Wiley & Sons, New York, pp. 234-237, 2001