DOI QR코드

DOI QR Code

Effect of High Temperature Annealing on the Characteristics of SiC Schottky Diodes

고온 열처리 공정이 탄화규소 쇼트키 다이오드 특성에 미치는 영향

  • 정희종 (동의대학교 전자정보통신공학부) ;
  • 방욱 (한국전기연구원 전력반도체그룹) ;
  • 강인호 (한국전기연구원 전력반도체그룹) ;
  • 김상철 (한국전기연구원 전력반도체그룹) ;
  • 한현숙 (경남대학교 전자전기공학부) ;
  • 김형우 (한국전기연구원 전력반도체그룹) ;
  • 김남균 (한국전기연구원 전력반도체그룹) ;
  • 이용재 (동의대학교 전자정보통신공학부)
  • Published : 2006.09.01

Abstract

The effects of high-temperature process required to fabricate the SiC devices on the surface morphology and the electrical characteristics were investigated for 4H-SiC Schottky diodes. The 4H-SiC diodes without a graphite cap layer as a protection layer showed catastrophic increase in an excess current at a forward bias and a leakage current at a reverse bias after high-temperature annealing process. Moreover it seemed to deviate from the conventional Schottky characteristics and to operate as an ohmic contact at the low bias regime. However, the 4H-SiC diodes with the graphite cap still exhibited their good electrical characteristics in spite of a slight increase in the leakage current. Therefore, we found that the graphite cap layer serves well as the protection layer of silicon carbide surface during high-temperature annealing. Based on a closer analysis on electric characteristics, a conductive surface transfiguration layer was suspected to form on the surface of diodes without the graphite cap layer during high-temperature annealing. After removing the surface transfiguration layer using ICP-RIE, Schottky diode without the graphite cap layer and having poor electrical characteristics showed a dramatic improvement in its characteristics including the ideality factor[${\eta}$] of 1.23, the schottky barrier height[${\Phi}$] of 1.39 eV, and the leakage current of $7.75\{times}10^{-8}\;A/cm^{2}$ at the reverse bias of -10 V.

References

  1. 송근호, 김남균, 방 욱, 김상철, 김형우, 김은동, 'Field ring 구조를 이용한 고전압 SiC schottky diode 제작', 한국전기전자재료학회 2002하계학술대회논문집 p. 350, 2002
  2. 정희종, 방 욱, 강인호, 김상철, 한현숙, 김남균, 이용재, '4H 탄화규소 쇼트키 다이오드에서 접합종단기법에 따른 항복전압 특성', 한국전기전자재료학회 2005하계학술대회논문집, p. 191, 2005
  3. B. Jayant Baliga, 'Power Semiconductor Devices', PWS publishing company, p. 182, 1995
  4. K. Kimoto and N. Inoue, 'Nitrogen ion implantation into a-SiC epitaxial layers', Phys. Status Silidi(a), Vol. 162, Iss. 1, p. 263, 2001
  5. G. Younes, G. Ferro, C. Jacquier, J. Dazord, and Y. Monteil, 'Comparison between Ar and $N_2$ for high-temperature treatment of 4H-SiC substrates', Materials Science Forum, p. 119, 2003
  6. M. A. Capano, S.-H. Ryu, J. A. Cooper, Jr., and M. R. Melloch, 'Surface morphology of ion implanted silicon carbide', Electronic Materials Conference, Charlottesville, VA, p. 24, 1998
  7. C. Tomas, C. Taylor, J. Griffin, W. L. Rose, M. G. Spencer, M. Capano, S. Rendakova, and K. Kornegay, 'Annealing of ion implantaion damage in SiC using a graphite mask', MRS Proc., Vol. 572, p. 45. 1999
  8. Vickram R. Vathulya and Marvin H. White, 'Characterization and performance comparsion of the power DIMOS structure fabricated with a reduced thermal budget in 4H and 6H-SiC', Solid-Stage Electronics, Vol. 44, Iss. 2, p. 309, 2000 https://doi.org/10.1016/S0038-1101(99)00237-3
  9. 송근호, 김남균, 방 욱, 김상철, 서길수, 김은동, 'SiC 웨이퍼의 이온 주입 손상 회복을 통한 macrostep 형성 억제', 한국전기전자재료학회 2002하계학술대회논문집, p, 346, 2002
  10. D. Tournier, A. Perez-Tomas, P. Godignon, J. Millan, H. Mank, D. Turover, D. Hinchley, and J. Rhodes, in: Proc. IEEE 17th Int, Symp, on Power Semiconductor Dev. and ICs(ISPSD), Santa Barbara, CA, USA, p. 239, 2005
  11. J. B. Tucker, S. Mitra, N. Papanicolaou, A. Siripuram, M. V. Rao, and O. W. Holland, 'Nitrogen and phosphorus implanted MESFET in semi-insulating 4H-SiC', Diamond and Related Materials, Vol. 11, Iss. 3-6, p. 392, 2002
  12. L. B. Ruppalt, S. Stafford, D. Yuan, K. A. Jones, M. H. Ervin, K. W. Kirchner, T. S. Zheleva, M. C. Wood, B. R. Geil, E. Forsythe, R. D. Vispute, and T. Venkatesan 'Using a PLD BN/AIN composite as an annealing cap for ion implanted SiC', Solid-State Electronics, Vol. 47, Iss. 2, p. 253, 2003 https://doi.org/10.1016/S0038-1101(02)00203-4
  13. W. Bahng, N.-K. Kim, S. C. Kim, G. H. Song, and E. D. Kim, 'Suppression of macrostep formation in 4H-SiC using a cap oxide layer', Mater. Sci. Forum, Vol. 389-393, p. 863, 2002
  14. W. Bahng, H. W. Kim, G. H. Song, N. K. Kim, S. C. Kim, K. S. Seo, and E. D. Kim, 'Trench formation on ion implanted SiC surfaces after thermal oxidation', Mater. Sci. Forum, Vol. 483-485, p. 777, 2005
  15. Y. Negoro, K. Katsumoto, and T. Kimoto, 'Flat surface after high-temperature annealing for phosphorus-ion implanted 4H-SiC (0001) using graphite cap', Mater, Sci, Forum, Vol. 457-460, p. 933, 2004