DOI QR코드

DOI QR Code

Characteristics of HfO2 Thin Films Using Wet Etching

습식식각을 이용한 HfO2 박막의 식각특성

  • Received : 2011.07.11
  • Accepted : 2011.07.28
  • Published : 2011.09.01

Abstract

Hafnium oxide ($HfO_2$) was very advantageous for substitute material of gate on existing transistor. $HfO_2$ has been widely studied due to high contact with polysilicon and thermal stability and also, it is easily etched by using HF solution. In this study, $HfO_2$ and thermal oxide films were etched by wet etch method using chemical etchant. Etch rate of $HfO_2$ and thermal oxide was linearly increased with increasing concentration of HF and temperature but etch rate of $HfO_2$ was higher than thermal oxide due to $H^+$, $F^-$, and $HF_2^-$ ions at below 0.5% concentration of HF. And also, etch selectivity was improved by adding Hydrazine as additive.

Keywords

References

  1. G. Wilk, R. M. Wallace, and J. M. Anthony, J. Appl. Phys., 89, 5243 (2001). https://doi.org/10.1063/1.1361065
  2. M. Houssa, R. Degraeve, P. W. Mertens, M. M. Heyns, J. S. Jeon, A. Halliyal, and B. Ogle, J. Appl. Phys., 86, 6462 (1999). https://doi.org/10.1063/1.371709
  3. B. H. Lee, K. Kang, W. J. Qi, R. Nich, Y. Jem, K. Onishi, and J. C. Lee, IEDM Tech. Dig., 133 (1999).
  4. B. H. Lee, L. Kang, R. Nich, W. Qi, and J. C. Lee, Appl. Phys. Lett., 76, 1926 (2000). https://doi.org/10.1063/1.126214
  5. L. Kang, B. H. Lee, W. Qi, Y. Jem, R. Nich, S. Gopalan, K. Onishi, and J. C. Lee, IEEE Electron. Dev. Lett., 21, 181 (2000). https://doi.org/10.1109/55.830975
  6. P. S. Lysaght, P. J. Chen, R. Bergmann, T. Messina, R. W. Murto, and H. R. Huff, J. Non-Cryst. Solids, 303, 54 (2002). https://doi.org/10.1016/S0022-3093(02)00964-X
  7. T. Ohmi, Scientific wet process technology for innovative LSI/FPD manufacturing (Taylor & Francis, London, 2006) p. 156.