Formation of Nickel Silicide from Atomic Layer Deposited Ni film with Ti Capping layer

  • 윤상원 (경북대학교 전자전기컴퓨터학부) ;
  • 이우영 (경북대학교 전자전기컴퓨터학부) ;
  • 양충모 (경북대학교 전자전기컴퓨터학부) ;
  • 나경일 (경북대학교 전자전기컴퓨터학부) ;
  • 조현익 (경북대학교 전자전기컴퓨터학부) ;
  • 하종봉 (경북대학교 전자전기컴퓨터학부) ;
  • 서화일 (한국기술교육대학교 전자공학과) ;
  • 이정희 (경북대학교 전자전기컴퓨터학부)
  • Published : 2007.06.08

Abstract

The NiSi is very promising candidate for the metallization in 60nm CMOS process such as FUSI(fully silicided) gate and source/drain contact because it exhibits non-size dependent resistance, low silicon consumption and mid-gap workfunction. Ni film was first deposited by using ALD (atomic layer deposition) technique with Bis-Ni precursor and $H_2$ reactant gas at $220^{\circ}C$ with deposition rate of $1.25{\AA}/cycle$. The as-deposited Ni film exhibited a sheet resistance of $5{\Omega}/{\square}$. RTP (repaid thermal process) was then performed by varying temperature from $400^{\circ}C$ to $900^{\circ}C$ in $N_2$ ambient for the formation of NiSi. The process window temperature for the formation of low-resistance NiSi was estimated from $600^{\circ}C$ to $800^{\circ}C$ and from $700^{\circ}C$ to $800^{\circ}C$ with and without Ti capping layer. The respective sheet resistance of the films was changed to $2.5{\Omega}/{\square}$ and $3{\Omega}/{\square}$ after silicidation. This is because Ti capping layer increases reaction between Ni and Si and suppresses the oxidation and impurity incorporation into Ni film during silicidation process. The NiSi films were treated by additional thermal stress in a resistively heated furnace for test of thermal stability, showing that the film heat-treated at $800^{\circ}C$ was more stable than that at $700^{\circ}C$ due to better crystallinity.

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