IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Electronics Tuesday Sessions
       Session EL-TuP

Paper EL-TuP8
A Study on the Germanosilicide Formation in the Ni/Si@sub 1-X@Ge@sub X@ System for CMOS Device Applications

Tuesday, October 30, 2001, 5:30 pm, Room 134/135

Session: Electronic Materials Poster Session
Presenter: H.-J. Choi, Yonsei University, Korea
Authors: H.-J. Choi, Yonsei University, Korea
D.-H. Ko, Yonsei University, Korea
J.-H. Ku, Samsung Electronics Co., Korea
C.-J. Choi, Samsung Electronics Co., Korea
S. Choi, Samsung Electronics Co., Korea
K. Fujihara, Samsung Electronics Co., Korea
H.-K. Kang, Samsung Electronics Co., Korea
C.-W. Yang, Sungkyunkwan University, Korea
Correspondent: Click to Email
Si@sub 1-X@Ge@sub X@ has been studied in many applications in order to resolve issues on size reduction in ULSI devices. For the application of Si@sub 1-X@Ge@sub X@ to ULSI devices, interactions with metals such as Co, Ti, or Ni should be investigated to show the SALICIDE process adaptability. In the application of Co, Ti in the Si@sub 1-X@Ge@sub X@ system, it has been reported that the Ge segregation and the film islanding occurs with the addition of Ge, which lead to the increase of gate resistance. Due to its low resistance, leakage current, and no pattern size dependence much attention is focused on the Ni-silicide for sub-100nm technology. Therefore, in this study, the solid-state reaction in Ni/Si@sub 1-X@Ge@sub X@ systems and the thermal stability of Ni/Si@sub 1-X@Ge@sub X@(X=0, 0.16, 0.25, and 0.29) were investigated. The silicidation was performed by RTP from 500°C to 980°C for 30sec under N@sub 2@ flow. Low resistive NiSi phases are not detected above 660°C in the case of Ni/poly-Si systems, while Ni(Si@sub 1-y@Ge@sub y@) phases are observed at above 820°C in Ni/Si@sub 1-X@Ge@sub X@ (X=0.16, 0.25, and 0.29) systems. When Ge is incorporated, germanosilicide on poly-Si@sub 1-X@Ge@sub X@ is unstable due to the formation and growth of Ge rich Si-Ge alloy grains between germanosilicide grains near free surface. This results in a layer inversion of Ni(Si@sub 1-y@Ge@sub y@) and Si@sub 1-X@Ge@sub X@ layers, and consequent increase in Rs values about 10@super 6@@ohm@/sq. above 620°C. Upon higher temperature annealing, the inverted grains grow and finally reach the free surface. Due to the incorporation of Ge, the phase transition to disilicide is delayed in the Ni/Si@sub 1-X@Ge@sub X@ system. Prior to the phase transition, inversion of germanosilicide layers and Si@sub 1-X@Ge@sub X@ layers occurs, which results in sharp increase in sheet resistance values at above 620°C.