# 원자현미경을 이용한 탄화규소 (SiC)의 국소산화

• 조영득 (광운대학교 전자재료공학과) ;
• 방욱 (한국전기연구원 재료응용연구단 고집적전원연구그룹) ;
• 김상철 (한국전기연구원 재료응용연구단 고집적전원연구그룹) ;
• 김남균 (한국전기연구원 재료응용연구단 고집적전원연구그룹) ;
• 구상모 (광운대학교 전자재료공학과)
• Published : 2009.08.01

#### Abstract

The local oxidation using an atomic force microscopy (AFM) is useful for Si-based fabrication of nanoscale structures and devices. SiC is a wide band-gap material that has advantages such as high-power, high-temperature and high-frequency in applications, and among several SiC polytypes, 4H-SiC is the most attractive polytype due to the high electron mobility. However, the AFM local oxidation of 4H-SiC for fabrication is still difficult, mainly due to the physical hardness and chemical inactivity of SiC. In this paper, we investigated the local oxidation of 4H-SiC surface using an AFM. We fabricated oxide patterns using a contact mode AFM with a Pt/Ir-coated Si tip (N-type, 0.01-0.025 ${\Omega}cm$) at room temperature, and the relative humidity ranged from 40 to 50 %. The height of the fabricated oxide pattern (1-3 nm) on SiC is similar to that of typically obtained on Si ($10^{15}^{\sim}10^{17}$ $cm^{-3}$). We perform the 2-D simulation to further analyze the electric field between the tip and the surface. We demonstrated that a specific electric field (4 ${\times}$ $10^7\;V/m$) and a doping concentration ($^{\sim}10^{17}$ $cm^{-3}$) is sufficient to switch on/off the growth of the local oxide on SiC.

#### References

1. J. S. Hwang, Z. S. Hu, Z. Y. You, T. Y. Lin, Chin L. Hsiao, and L. W. Tu, 'Local oxidation of InN and GaN using an atomic force microscope', Nanotechnology, Vol. 17, p. 859, 2006 https://doi.org/10.1088/0957-4484/17/3/041
2. J. S. Hwang, Z. Y. You, S. Y. Lin, Z. S. Hu, C. T. Wu, C. W. Chen, and K. H. Chen, 'Effect of gold coating on local oxidation using an atomic force microscope', Appl. Phys. Lett., Vol. 86, p. 161901, 2005 https://doi.org/10.1063/1.1901804
3. J. S. Hwang, Z. S. Hu, T. Y. Lu, L. W. Chen, S. W. Chen, T. Y. Lin, C.-L. Hsiao, K.-H. Chen, and L.-C. Chen, 'Photo-assisted local oxidation of GaN using an atomic force microscope', Nanotechnology, Vol. 17, p. 3299, 2006 https://doi.org/10.1088/0957-4484/17/13/036
4. X. N. Xie, H. J. Chung, C. H. Sow, and A. T. S. Wee, 'Native oxide decomposition and local oxidation of 6H-SiC (0001) surface by atomic force microscopy', Appl. Phys. Lett., Vol. 84, p. 4914, 2004 https://doi.org/10.1063/1.1728305
5. Howell, R. S., Buchoff, S., Van Campen, S. McNutt, T. R. Ezis, A., Nechay, B., Kirby, C. F., Sherwin, M. E., Clarke, R. C., and Singh, R., 'A 10-kV large-area 4H-SiC power DMOSFET with stable subthreshold behavior independent of temperature', IEEE Trans. Electron Devices, Vol. 55, No. 8, p. 1807, 2008 https://doi.org/10.1109/TED.2008.928204
6. E. Dubois, P. A. Fontaine, and D. Stievenard, 'Characterization of scanning tunneling microscopy and atomic force microscopy- based techniques for nanolithography on hydrogen-passivated silicon', J. App. Phys., Vol. 84, No. 4, p. 1776, 1998 https://doi.org/10.1063/1.368334
7. P. Mazur, M. Grodzicki, S. Zuber, and A. Ciszewski, 'Current patterning of 6H–SiC(0 0 0 1) surface by AFM', Appl. Surface Science, Vol. 254, p. 4332, 2008 https://doi.org/10.1016/j.apsusc.2008.01.046