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Characteristics of poly-Si TFTs using Excimer Laser Annealing Crystallization and high-k Gate Dielectrics

Excimer Laser Annealing 결정화 방법 및 고유전 게이트 절연막을 사용한 poly-Si TFT의 특성

  • 이우현 (광운대학교 전자재료공학과) ;
  • 조원주 (광운대학교 전자재료공학과)
  • Published : 2008.01.01

Abstract

The electrical characteristics of polycrystalline silicon (poly-Si) thin film transistor (TFT) crystallized by excimer laser annealing (ELA) method were evaluated, The polycrystalline silicon thin-film transistor (poly-Si TFT) has higher electric field-effect-mobility and larger drivability than the amorphous silicon TFT. However, to poly-Si TFT's using conventional processes, the temperature must be very high. For this reason, an amorphous silicon film on a buried oxide was crystallized by annealing with a KrF excimer laser (248 nm)to fabricate a poly-Si film at low temperature. Then, High permittivity $HfO_2$ of 20 nm as the gate-insulator was deposited by atomic layer deposition (ALD) to low temperature process. In addition, the solid phase crystallization (SPC) was compared to the ELA method as a crystallization technique of amorphous-silicon film. As a result, the crystallinity and surface roughness of poly-Si crystallized by ELA method was superior to the SPC method. Also, we obtained excellent device characteristics from the Poly-Si TFT fabricated by the ELA crystallization method.

Keywords

References

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