Hysteresis Phenomenon of Hydrogenated Amorphous Silicon Thin Film Transistors for an Active Matrix Organic Light Emitting Diode

능동형 유기 발광 다이오드(AMOLED)에서 발생하는 수소화된 비정질 실리콘 박막 트랜지스터(Hydrogenated Amorphous Silicon Thin Film Transistor)의 이력 (Hysteresis) 현상

  • 최성환 (서울대학교 전기공학부) ;
  • 이재훈 (서울대학교 전기공학부) ;
  • 신광섭 (서울대학교 전기공학부) ;
  • 박중현 (서울대학교 전기공학부) ;
  • 신희선 (서울대학교 전기공학부) ;
  • 한민구 (서울대학교 전기공학부)
  • Published : 2007.01.01

Abstract

We have investigated the hysteresis phenomenon of a hydrogenated amorphous silicon thin film transistor (a-Si:H TFT) and analyzed the effect of hysteresis phenomenon when a-Si:H TFT is a pixel element of active matrix organic light emitting diode (AMOLED). When a-Si:H TFT is addressed to different starting gate voltages, such as 10V and 5V, the measured transfer characteristics with 1uA at $V_{DS}$ = 10V shows that the gate voltage shift of 0.15V is occurred due to the different quantities of trapped charge. When the step gate-voltage in the transfer curve is decreased from 0.5V to 0.05V, the gate-voltage shift is decreased from 0.78V to 0.39V due to the change of charge do-trapping rate. The measured OLED current in the widely used 2-TFT pixel show that a gate-voltage of TFT in the previous frame can influence OLED current in the present frame by 35% due to the change of interface trap density induced by different starting gate voltages.

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