中国物理B ›› 2009, Vol. 18 ›› Issue (8): 3490-3494.doi: 10.1088/1674-1056/18/8/059

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High energy electron radiation effect on Ni/4H-SiC SBD and Ohmic contact

张林, 张义门, 张玉明, 韩超, 马永吉   

  1. School of Microelectronics and Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi'an 710071, China
  • 收稿日期:2008-12-08 修回日期:2009-03-19 出版日期:2009-08-20 发布日期:2009-08-20
  • 基金资助:
    Project~supported~by~the National Natural Science Foundation of China (Grant No 60606022), the Xian Applied Materials Foundation (Grant No XA-AM-200702) and the Advanced Research Foundation (Grant No 9140A08050508).

High energy electron radiation effect on Ni/4H-SiC SBD and Ohmic contact

Zhang Lin(张林)†, Zhang Yi-Men(张义门), Zhang Yu-Ming(张玉明), Han Chao(韩超), and Ma Yong-Ji(马永吉)   

  1. School of Microelectronics and Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, Xidian University, Xi'an 710071, China
  • Received:2008-12-08 Revised:2009-03-19 Online:2009-08-20 Published:2009-08-20
  • Supported by:
    Project~supported~by~the National Natural Science Foundation of China (Grant No 60606022), the Xian Applied Materials Foundation (Grant No XA-AM-200702) and the Advanced Research Foundation (Grant No 9140A08050508).

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摘要： The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were fabricated, and irradiated with 1~MeV electrons up to a dose of 3.43× 1014~e/cm-2. After radiation, the forward currents of the SBDs at 2~V decreased by about 50%, and the reverse currents at -200~V increased by less than 30%. Schottky barrier height (φ B ) of the Ni/4H-SiC SBD increased from 1.20~eV to 1.21~eV under 0~V irradiation bias, and decreased from 1.25~eV to 1.19~eV under -30~V irradiation bias. The degradation of φ B could be explained by the variation of interface states of Schottky contacts. The on-state resistance (Rs) and the reverse current increased with the dose, which can be ascribed to the radiation defects in bulk material. The specific contact resistance (\rhoc) of the Ni/SiC Ohmic contact increased from 5.11× 105~Ωega.cm2 to 2.97× 10-4~Ωega.cm2.

Abstract: The Ni/4H-SiC Schottky barrier diodes (SBDs) and transfer length method (TLM) test patterns of Ni/4H-SiC Ohmic contacts were fabricated, and irradiated with 1 MeV electrons up to a dose of 3.43×1014 e/cm-2. After radiation, the forward currents of the SBDs at 2 V decreased by about 50%, and the reverse currents at -200 V increased by less than 30%. Schottky barrier height ($\phi_{\rm B}$) of the Ni/4H-SiC SBD increased from 1.20 eV to 1.21 eV under 0 V irradiation bias, and decreased from 1.25 eV to 1.19 eV under -30 V irradiation bias. The degradation of $\phi_{\rm B}$ could be explained by the variation of interface states of Schottky contacts. The on-state resistance (Rs) and the reverse current increased with the dose, which can be ascribed to the radiation defects in bulk material. The specific contact resistance ($\rho_{\rm c}$) of the Ni/SiC Ohmic contact increased from 5.11× 105 $\Omega\cdot$cm2 to 2.97×10-4 $\Omega\cdot$cm2.

Key words: silicon carbide, Schottky barrier diode, Ohmic contact, electron radiation

中图分类号:  (Junction diodes)

  • 85.30.Kk
61.80.Fe (Electron and positron radiation effects) 73.30.+y (Surface double layers, Schottky barriers, and work functions) 73.40.Cg (Contact resistance, contact potential) 73.40.Ns (Metal-nonmetal contacts)