中国物理B ›› 2007, Vol. 16 ›› Issue (6): 1753-1756.doi: 10.1088/1009-1963/16/6/046

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The fabrication of nickel silicide ohmic contacts to n-type 6H-silicon carbide

乔大勇1, 孙磊1, 郭辉2, 张义门2, 张玉明2   

  1. (1)Micro and Nano Electromechanical Systems Laboratory, Northwestern Polytechnical University, Xi'an 710072, China; (2)Microelectronic School, Xidian University, Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Xi'an 710071, China
  • 收稿日期:2006-09-19 修回日期:2006-10-30 出版日期:2007-06-20 发布日期:2007-06-20
  • 基金资助:
    Project supported by the National Basic Research Program of China (Grant No~2002CB311904), the National Defense Basic Research Program of China (Grant No~51327010101) and the National Natural Science Foundation of China (Grant No~60376001).

The fabrication of nickel silicide ohmic contacts to n-type 6H-silicon carbide

Guo Hui(郭辉)a) † , Zhang Yi-Men(张义门)a), Qiao Da-Yong(乔大勇)b), Sun Lei(孙磊)b), and Zhang Yu-Ming(张玉明)a)   

  1. a Microelectronic School, Xidian University, Key Laboratory of Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Xi'an 710071, China; b  Micro and Nano Electromechanical Systems Laboratory, Northwestern Polytechnical University, Xi'an 710072, China
  • Received:2006-09-19 Revised:2006-10-30 Online:2007-06-20 Published:2007-06-20
  • Supported by:
    Project supported by the National Basic Research Program of China (Grant No~2002CB311904), the National Defense Basic Research Program of China (Grant No~51327010101) and the National Natural Science Foundation of China (Grant No~60376001).

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摘要： This paper reports that the nickel silicide ohmic contacts to n-type 6H-SiC have been fabricated. Transfer length method test patterns with NiSi/SiC and NiSi$_{2}$/SiC structure are formed on N-wells created by N$^{ + }$ ion implantation into Si-faced p-type 6H-SiC epilayer respectively. NiSi and NiSi$_{2}$ films are prepared by annealing the Ni and Si films separately deposited. A two-step annealing technology is performed for decreasing of oxidation problems occurred during high temperature processes. The specific contact resistance $\rho _{c}$ of NiSi contact to n-type 6H-SiC as low as 1.78$\times $10$^{ - 6}\Omega $cm$^{2}$ is achieved after a two-step annealing at 350~${^\circ}$C for 20 min and 950${^\circ}$C for 3 min in N$_{2}$. And 3.84$\times $10$^{ - 6}\Omega $cm$^{2}$ for NiSi$_{2}$ contact is achieved. The result for sheet resistance $R_{\rm sh}$ of the N$^{ + }$ implanted layers is about 1210$\Omega /\square$. X-ray diffraction analysis shows the formation of nickel silicide phases at the metal/n-SiC interface after thermal annealing. The surfaces of the nickel silicide after thermal annealing are analysed by scanning electron microscope.

关键词: ohmic contact, silicon carbide, nickel silicide, N+ ion implantation

Abstract: This paper reports that the nickel silicide ohmic contacts to n-type 6H-SiC have been fabricated. Transfer length method test patterns with NiSi/SiC and NiSi$_{2}$/SiC structure are formed on N-wells created by N$^{ + }$ ion implantation into Si-faced p-type 6H-SiC epilayer respectively. NiSi and NiSi$_{2}$ films are prepared by annealing the Ni and Si films separately deposited. A two-step annealing technology is performed for decreasing of oxidation problems occurred during high temperature processes. The specific contact resistance $\rho _{c}$ of NiSi contact to n-type 6H-SiC as low as 1.78$\times $10$^{ - 6}\Omega $cm$^{2}$ is achieved after a two-step annealing at 350~${^\circ}$C for 20 min and 950${^\circ}$C for 3 min in N$_{2}$. And 3.84$\times $10$^{ - 6}\Omega $cm$^{2}$ for NiSi$_{2}$ contact is achieved. The result for sheet resistance $R_{\rm sh}$ of the N$^{ + }$ implanted layers is about 1210$\Omega /\square$. X-ray diffraction analysis shows the formation of nickel silicide phases at the metal/n-SiC interface after thermal annealing. The surfaces of the nickel silicide after thermal annealing are analysed by scanning electron microscope.

Key words: ohmic contact, silicon carbide, nickel silicide, N+ ion implantation

中图分类号:  (Contact resistance, contact potential)

  • 73.40.Cg
61.05.cp (X-ray diffraction) 68.55.-a (Thin film structure and morphology) 68.55.Ln (Defects and impurities: doping, implantation, distribution, concentration, etc.) 81.40.Ef (Cold working, work hardening; annealing, post-deformation annealing, quenching, tempering recovery, and crystallization)