A Study on Low Temperature Sequential Lateral Solidification(SLS) Poly-Si Thin Film Transistors(TFT′s) with Molybdenum Gate

Molybdenum 게이트를 적용한 저온 SLS 다결정 TFT′s 소자 제작과 특성분석에 관한 연구

  • 고영운 (삼성전자 DS총괄 AMLCD 사업부) ;
  • 박정호 (고려대학 공과학과 전기공학과) ;
  • 김동환 (고려대학 공과학과 재료공학부) ;
  • 박원규 (LGPhilips-LCD 연구소)
  • Published : 2003.06.01

Abstract

In this paper, we present the fabrication and the characteristic analysis of sequential lateral solidification(SLS) poly-Si thin film transistors(TFT's) with molybdenum gate for active matrix liquid displays (AMLCD's) pixel controlling devices. The molybdenum gate is applied for the purpose of low temperature processing. The maximum processing temperature is 55$0^{\circ}C$ at the dopant thermal annealing step. The SLS processed poly-Si film which is reduced grain and grain boundary effect, is applied for the purpose of electrical characteristics improvements of poly-Si TFT's. The fabricated low temperature SLS poly-Si TFT's had a varying the channel length and width from 10${\mu}{\textrm}{m}$ to 2${\mu}{\textrm}{m}$. And to analyze these devices, extract electrical characteristic parameters (field effect mobility, threshold voltage, subthreshold slope, on off current etc) from current-voltage transfer characteristics curve. The extract electrical characteristic of fabricated low temperature SLS poly-Si TFT's showed the mobility of 100~400cm$^2$/Vs, the off current of about 100pA, and the on/off current ratio of about $10^7$. Also, we observed that the change of grain boundary according to varying channel length is dominant for the change of electrical characteristics more than the change of grain boundary according to varying channel width. Hereby, we comprehend well the characteristics of SLS processed poly-Si TFT's witch is recrystallized to channel length direction.

Keywords

fabrication;low temperature;Sequential Lateral Solidification(SLS);poly-silicon;thin film transistor(TFT)

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