• Title/Summary/Keyword: poly-Si TFTs

Search Result 175, Processing Time 0.027 seconds

Self-Aligned Offset Poly-Si TFT using Photoresist reflow process (Photoresist reflow 공정을 이용한 자기정합 오프셋 poly-Si TFT)

  • Yoo, Juhn-Suk;Park, Cheol-Min;Min, Byung-Hyuk;Han, Min-Koo
    • Proceedings of the KIEE Conference
    • /
    • 1996.07c
    • /
    • pp.1582-1584
    • /
    • 1996
  • The polycrystalline silicon thin film transistors (poly-Si TFT) are the most promising candidate for active matrix liquid crystal displays (AMLCD) for their high mobilities and current driving capabilities. The leakage current of the poly-Si TFT is much higher than that of the amorphous-Si TFT, thus larger storage capacitance is required which reduces the aperture ratio fur the pixel. The offset gated poly-Si TFTs have been widely investigated in order to reduce the leakage current. The conventional method for fabricating an offset device may require additional mask and photolithography process step, which is inapplicable for self-aligned source/drain ion implantation and rather cost inefficient. Due to mis-alignment, offset devices show asymmetric transfer characteristics as the source and drain are switched. We have proposed and fabricated a new offset poly-Si TFT by applying photoresist reflow process. The new method does not require an additional mask step and self-aligned ion implantation is applied, thus precise offset length can be defined and source/drain symmetric transfer characteristics are achieved.

  • PDF

Degradation of Polycrystalline Silicon Thin Film Transistor by Inducing Stress (스트레스 인가에 의한 다결정 실리콘 박막 트랜지스터의 열화 특성)

  • 백도현;이용재
    • Proceedings of the IEEK Conference
    • /
    • 2000.06b
    • /
    • pp.322-325
    • /
    • 2000
  • N-channel poly-Si TFT, Processed by Solid Phase Crystalline(SPC) on a glass substrate, has been investigated by measuring its electrical properties before and after electrical stressing. It is observed that the threshold voltage shift due to electrical stress varies with various stress conditions. Threshold voltages measured in 1.5$\mu\textrm{m}$ and 3$\mu\textrm{m}$ poly-Si TFTs are 3.3V, 3.V respectively. With the threshold voltage shia the degradation of transconductance(G$\_$m/) and subthreshold swing(S) is also observed.

  • PDF

A New Level Shifter using Low Temperature poly-Si TFTs

  • Shim, Hyun-Sook;Kim, Jong-Hun;Cho, Byoung-Chul;Kwon, Oh-Kyong
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2004.08a
    • /
    • pp.1015-1018
    • /
    • 2004
  • We proposed a new cross-coupled level shifter circuit using low temperature poly-Si(LTPS) TFT. The proposed level shifter can operate on low input voltage in spite of low mobility and widely varying high threshold voltage of LTPS TFT. Also, the proposed level shifter operates at high frequency and reduces power consumption for having fast rising and falling time and shortening period flowing short-circuit currents.

  • PDF

Comparative Pixel Characteristics of ELA and SMC poly-Si TETs for the Development of Wide-Area/High-Quality TFT-LCD (대화면/고화질 TFT-LCD 개발을 위하여 ELA 및 SMC로 제작된 다결정 실리콘 박막 트랜지스터의 화소 특성 비교)

    • Journal of the Korean Vacuum Society
    • /
    • v.10 no.1
    • /
    • pp.72-80
    • /
    • 2001
  • In this paper, we present a systematic method of extracting the input parameters of poly-Si TFT(Thin-Film Transistor) for Spice simulations. This method has been applied to two different types of poly-Si TFTs such as ELA (Excimer Laser Annealing) and SMC (Silicide Mediated Crystallization) with good fitting results to experimental data. Among the Spice circuit simulators, the PSpice has the GUI(graphic user interface) feature making the composition of complicated circuits easier. We added successfully the poly-Si TFT model of AIM-Spice to the PSpice simulator, and analyzed easily to compare the electrical characteristics of pixels without or with the line RC delay. In the comparative results, the ELA poly-Si TFT is superior to the SMC poly-Si TFT in the charging time and the kickback voltage for the TFT-LCD (Thin Film Transistor-Liquid Crystal Display).

  • PDF

5-TFT OLED Pixel Circuit Compensating Threshold Voltage Variation of p-channel Poly-Si TFTs (p-채널 다결정 실리콘 박막 트랜지스터의 문턱전압 변동을 보상할 수 있는 5-TFT OLED 화소회로)

  • Chung, Hoon-Ju
    • The Journal of the Korea institute of electronic communication sciences
    • /
    • v.9 no.3
    • /
    • pp.279-284
    • /
    • 2014
  • This paper proposes a novel OLED pixel circuit to compensate the threshold voltage variation of p-channel low temperature polycrystalline silicon thin-film transistors (LTPS TFTs). The proposed 5-TFT OLED pixel circuit consists of 4 switching TFTs, 1 OLED driving TFT and 1 capacitor. One frame of the proposed pixel circuit is divided into initialization period, threshold voltage sensing and data programming period, data holding period and emission period. SmartSpice simulation results show that the maximum error rate of OLED current is -4.06% when the threshold voltage of driving TFT varies by ${\pm}0.25V$ and that of OLED current is 9.74% when the threshold voltage of driving TFT varies by ${\pm}0.50V$. Thus, the proposed 5T1C pixel circuit can realize uniform OLED current with high immunity to the threshold voltage variation of p-channel poly-Si TFT.

The characteristics of poly-Si(ELA) TFTs with various channel lengths (다양한 채널 길이에 따른 ELA를 이용한 poly-Si TFT의 특징)

  • Son, Hyuk-Joo;Kim, Jae-Hong;Lee, Jeoung-In;Yi, Jun-Sin
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2007.06a
    • /
    • pp.91-92
    • /
    • 2007
  • 이 논문에서는 다양한 채널길이에 따른 n-채널 다결정 실리콘 TFT의 특징을 보고한다. Excimer laser annealing (ELA)를 이용한 다결정 실리콘은 디스플레이의 재료로써 줄은 특성을 갖는다. 유리기판 위에 buffered oxide 층을 올리고 ELA 처리를 하여 다결정 실리콘을 제작 하였다. 그 위에 $SiO_2$, $SiN_x$를 증착시켜 n-채널 다결정 실리콘 TFT를 만들었다. 다양한 채널의 길이에 따른 n-채널 TFT의 문턱전압 ($V_{TH}$), ON/OFF 전류비($I_{ON}/I_{OFF}$), 포화 전륙(IDSAT)를 조사하였다. 그 결과 채널의 길이가 짧은 소자에서 더 줄은 TFT의 특징이 나타난다.

  • PDF

Effective Annealing and Crystallization of Si film for Advanced TFT System

  • Noguchi, Takashi
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2009.10a
    • /
    • pp.254-257
    • /
    • 2009
  • The crystallization and activated annealing effect of Si films using an excimer laser and a new CW blue laser are described comparing with furnace annealing (SPC) for the application of advanced TFTs and future applications. Currently, pulsed ELA is used extensively as a LTPS process on glass substrates as the efficiency is high in UV region for thin Si film of 40- 60 nm thickness. ELA enables extremely low resistivity for both n- and p-typed Si films. On the other hand, CW BLDA enables the smooth Si surface having arbitral grains from micro-grains to anisotropic huge grain structure only controlling its power density.

  • PDF

Poly-Si TFT Fabricated at 170$^{\circ}C$ Using ICP-CVD and Excimer Laser Annealing for Plastic Substrates

  • Han, Sang-Myeon;Shin, Moon-Young;Park, Hyun-Joong;Lee, Hye-Jin;Han, Min-Koo
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2004.08a
    • /
    • pp.1003-1006
    • /
    • 2004
  • We have fabricated poly-Si TFTs at 170$^{\circ}C$ using inductively coupled plasma chemical vapor deposition (ICP-CVD) and excimer laser annealing (ELA). A Poly-Si film with large grains exceeding 5000${\AA}$ and a $SiO_2$ film with high breakdown field are deposited by ICP-CVD. A high mobility exceeding 100$cm^2$/Vs with a low sub-threshold swing of 0.76V/dec was obtained.

  • PDF