一种非晶硅薄膜晶体管栅极驱动电路

非晶硅薄膜晶体管(Amorphous Silicon Thin Film Transistors,a-Si TFT)具有器件性能均匀、成本低、适用于大面积显示的优点,是平板显示技术的主流基板材料。近年来由于集成栅极驱动电路(Gate Drivers Integrated in Array,GIA)在非晶硅薄膜晶体管液晶显示器中的应用,不仅能节省工艺步骤,降低成本,而且边框美观对称,使非晶硅薄膜晶体管液晶显示屏更加受到消费者的欢迎。但是由于非晶硅电子迁移率相对较低,栅极驱动电路仍占用较大空间,尤其是随着显示产品解析度的增加,产品边框变窄,驱动电路的版图空间变小,导致驱动电路的设计越来越困难。文章提出了一种新型栅极驱动电路,有效提高了a-Si TFT GIA的驱动能力,降低了版图面积,增加了a-Si TFT在高分辨、窄边框产品市场的竞争力。     

TFT AMLCD像素矩阵电路中栅延迟的模拟研究

建立了ａ－ＳｉＴＦＴＡＭＬＣＤ的等效电路模型,综合考虑栅信号线电阻、栅与源信号线的交叠电容以及ＴＦＴ导电沟道电容构成的ＲＣ（ＲｅｓｉｓｔｉｖｉｔｙＣａｐａｃｉｔａｎｃｅ）常数,模拟计算了栅信号延迟对液晶显示屏尺寸、显示分辨率及栅信号电极材料的依赖关系,为实现器件优化设计提供参考。     

薄有源层非晶硅薄膜晶体管特性的研究

本文研究了薄ａ－Ｓｉ：Ｈ有源层结构的ａ－Ｓｉ：Ｈ ＴＦＴ的特性，实验结果表明，当ａ－Ｓｉ：Ｈ层的厚度小于一个临界值时，ａ－Ｓｉ：Ｈ厚度的变化对ａ－Ｓｉ：Ｈ ＴＦＴ静态特性的影响明显增大，本文中详细分析了有源层背面空间电荷层对ａ－Ｓｉ：Ｈ ＴＦＴ特性的影响，从表面有效空间电荷层的概念出发，从理论上分析了有源层厚度与阈值电压的关系，计算的临界有源层厚度为１３０ｎｍ，这与实验结果基本一致。     

Gated-four-probe a-Si:H TFT structure: a new technique to measurethe intrinsic performance of a-Si:H TFT

In this letter, a new technique based on gated-four-probe hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) structure is proposed. This new technique allows the determination of the intrinsic performance of a-Si:H TFT without any influence from source/drain series resistances. In this method, two probes within a conventional a-Si:H TFT are used to measure the voltage difference within a channel. By correlating this voltage difference with the drain-source current induced by applied gate bias, the a-Si:H TFT intrinsic performance, such as mobility, threshold voltage, and field-effect conductance activation energy, can be accurately determined without any influence from source/drain series resistances     

Schottky-contact gated-four-probe a-Si:H TFT structure: a newstructure to investigate the electrical instability of a-Si:H TFT

In this letter, we describe a new device structure, the Schottky-contact (SC) gated-four-probe (GFP) hydrogenated amorphous silicon (a-Si:H) thin-film transistor (TFT) structure, that can be used to study the electrical instability of a-Si:H TFTs induced by bias-temperature-stress (BTS). In this SC-GFP TFT structure, the evolution of both electron and hole conduction characteristics can he studied before and after BTS without the influence of source-drain contacts. We observed that low-bias negative stress induces a reduction in the deep-gap state density, while high-bias negative stress mainly causes trapping of holes in the gate-insulator. On the other hand, positive BTS induces mainly the trapping of electrons in the gate-insulator, which causes positive shifts of both electron and hole conduction characteristics     

Effect of SiNx Gate Dielectric Deposition Power and Temperature on a-Si:H TFT Stability

The stability of thin-film transistors (TFTs) of hydrogenated amorphous-silicon (a-Si:H) against gate-bias stress is improved by raising the deposition power and temperature of the silicon nitride gate dielectric. We studied the effects of power density between 22 and 110 mW/cm² and temperature between 150degC and 300degC . The time needed to shift the threshold voltage by 2 V varies by a factor of 12 between low power and low temperature, and high power and high temperature. These results highlight the importance of fabricating a-Si:H TFTs on flexible plastic with the SiN_x gate dielectric deposited at the highest possible power and temperature.     

高性能a-Si:H TFT开关器件的研制

介绍了ａ－Ｓｉ：ＨＴＦＴ开关器件的有源层、栅绝缘层、欧接触层以及界面特性的研究工作。研制了ａ－Ｓｉ：ＨＴＦＴ单管器件,其开关电流达到６个数量级,为最终研制ａ－Ｓｉ：ＨＴＦＴＡＭＬＣＤ在奠定了坚实的基础。     

塑料基底a-Si∶H TFT制备技术

采用PECVD工艺,在300℃下在50μm厚的Kapton E高分子塑料片上制备了底栅结构a-Si∶H TFT阵列(20×20)。用傅里叶变换红外光谱仪表征了a-Si∶H薄膜的结构,用二探针法和四探针法分别表征了a-Si∶H薄膜和n+a-Si∶H薄膜的电导率。a-Si∶H薄膜中的H(原子数分数)约为15.6%,H主要以Si H和Si H2基团的形式存在,其电导率为8.2×10-7~8.8×10-6S/cm;n+a-Si∶H薄膜的电导率为3.8×10-3S/cm。所制备的TFT具有以下性能:Ioff≈1×10-14A,Ion≈1×10-9A,Ion/Ioff≈105,Vth≈5V,μ≈0.113cm2/(V.s),S≈2.5V/dec,满足TFT-LCD等平板显示器件的开关寻址电路要求。     

a—Si：H TFT自对准工艺的研究

实验研究了自对准结构的ａ－Ｓｉ：Ｈ ＴＦＴ的制备工艺，对其中关键的底部曝光和顶胶工艺进行了详细的研究和分析，对制备工艺和结构参数进行了合理的优化，成功地制备出自对准结构的ａ－Ｓｉ：Ｈ ＴＦＴ。对影响自对准结构ａ－Ｓｉ：Ｈ ＴＦＴ特性的主要因素进行了详细的分析，提出了一种新颖的双有源层结构的ａ－Ｓｉ：Ｈ ＴＦＴ，可以有效地改善ａ－Ｓｉ：Ｈ ＴＦＴ的开态特性，其通断电流比ＩＯＮ／ＩＯＦＦ〉１０＾５。     

A new a-Si:H TFT pixel circuit compensating the threshold voltage shift of a-Si:H TFT and OLED for active matrix OLED

We propose a new hydrogenated amorphous silicon thin-film transistor (a-Si:H TFT) pixel circuit for an active matrix organic light-emitting diode (AMOLED) employing a voltage programming. The proposed a-Si:H TFT pixel circuit, which consists of five switching TFTs, one driving TFT, and one capacitor, successfully minimizes a decrease of OLED current caused by threshold voltage degradation of a-Si:H TFT and OLED. Our experimental results, based on the bias-temperature stress, exhibit that the output current for OLED is decreased by 7% in the proposed pixel, while it is decreased by 28% in the conventional 2-TFT pixel.     

a—SiNx：H薄膜对a—Si：H TFT阈值电压的影响

介绍了测定a－Si：HTFT闽值电压的实验方法。重点研究了改变a－SiNx：H薄膜淀积时反应气体NH3／SiH4流速比以及a－SiNx:H膜厚对a－Si：HTFT阈值电压的影响。对实验结果进行了分析。实验结果表明：a－Si:HTFT的阈值电压随a－SiNx：H的膜厚增加而增大；增大X－SiNx：H薄膜淀积时NH3／SiH4气体流速比，可明显减小a-Si:HTFT的阈值电压。     

a—Si：H TFT有源矩阵制造技术的研究

对ａ：Ｓｉ：Ｈ ＴＦＴ有源矩阵的一些关键制造工艺进行研究。研究了Ｔａ２Ｏ５／ａ－ＳｉＮｘ双绝缘层的制备技术，提出了一种新的双有源层结构ａ－Ｓｉ：Ｈ ＴＦＴ来降低背光源对器件特性的影响，研制的ａ－Ｓｉ：Ｈ ＴＦＴ有源矩阵实现了彩色视频信号的动态显示。     

Dependence of Threshold Voltage of a-Si:H TFT on a-SiN_x:H Film

ＤｅｐｅｎｄｅｎｃｅｏｆＴｈｒｅｓｈｏｌｄＶｏｌｔａｇｅｏｆａ－Ｓｉ：ＨＴＦＴｏｎａ－ＳｉＮｘ：ＨＦｉｌｍ①ＸＩＯＮＧＺｈｉｂｉｎ，ＷＡＮＧＣｈａｎｇ’ａｎ，ＸＵＺｈｏｎｇｙａｎｇ，ＺＯＵＸｕｅｍｅｉ，ＺＨＡＯＢｏｆａｎｇ，ＤＡＩＹｏｎｇｂｉｎｇ，Ｗ...     

Dependence of Threshold Voltage of a-Si:H TFT on a-SiNx:H Film^①

The relation between threshold voltage for hydrogenated amorphous silicon thin film transistors(a-Si:HTFTs)and deposition conditions for hydrogenated amorphous silicon nitride(a-SiNx:H)films is investigated.It is observed that the threshold voltage,Vth,of a-Si:HTFT increases with the increase of the thickness of a-SiNx:H film,and the threshold voltage is reduced apparently with the increase of NH3/SiH4 gas flow rate ratio.     

用于TFT有源层的Ar~+激光结晶a-Si:H的性质(英文)

This paper demonstrates the technological approach to the high performance a-Si:H thin film transistor (TFT) fabricated by the Ar+ laser-crystallization technique on the fused quartz substrates. The a-Si:H films for the active layer of TFT were prepared in a capacitively coupled glow-discharge deposition system. The films were crystallized by CW Ar+ laser scanning at low speeds (3-5 cm/s). The laser power ranges from 2.5W to 5.0W. The TEM cross-section micrograph illustrates that a liquid phase laser crystallization region (LP-LCR) has defect-free of structure with a grain size of the order of handreds of micron. In the Raman spectrum of LP-LCR, 475 cm-1 peak of a-Si:H disappears and 520 cm-1 peak of c-Si becomes stronger and sharper. The value of conductivity in the layer of LP-LCR is five orders of magnitude larger than the one in asepositedd a-Si:H film. We also discussed some problems to be overcome in application of a-Si : H TFTs in LCD.     

PECVD a—Si：H薄膜对TFT有源矩阵性能的影响及其淀积工艺研究

分析了a－Si：HTFT有源层──a－Si：H薄膜质量和厚度对于a－Si：HTFT关键性指标（通断电流比、阈值电压、响应时间、开口率）的影响，深入、详细地研究了PECVD衬底温度、RF功率和频率、气体流量和反应室气压等淀积工艺参数对a—Si：H薄膜组分、结构的影响，并在实验的基础上给出了它们之间的关系曲线，确定了最佳淀积工艺参数，从而获得了高性能的7.5cm372×276象素a－Si：HTFT有源矩阵。     

Structure and properties of a-Si:H films grown by cyclic deposition

Amorphous hydrogenated silicon films obtained by cyclic deposition with intermediate annealing in hydrogen plasma were studied. a-Si:H films deposited under optimal conditions are photosensitive (photoconductivity to dark conductivity ratio σ_ph/σ_d is as high as 10⁷ under 20 mW cm^?2 illumination in the visible region of the spectrum) and have an optical gap (E _g ) and activation energy of conductivity (E _a ) of 1.85 and 0.91 eV, respectively. Electron microscopy studies revealed a clearly pronounced layered structure of a-Si:H films and the presence of nanocrystalline inclusions in the amorphous matrix.     

Asymmetric Electrical Properties of Corbino a-Si:H TFT and Concepts of Its Application to Flat Panel Displays

Inverted stagger hydrogenated-amorphous-silicon (a-Si:H) Corbino thin-film transistors (TFTs) were fabricated with a five-photomask process used in the processing of the active-matrix liquid-crystal displays (AM-LCD). The authors show that the a-Si:H Corbino TFT has the asymmetric electrical characteristics under different drain-bias conditions. To accommodate for these differences when the electrical device parameters are extracted, the authors developed asymmetric geometric factors. The ON-OFF current ratio can be significantly enhanced by choosing the outer electrode as the drain, while the field-effect mobility and threshold voltage are identical when different drain-bias conditions are used. Finally, the authors developed concepts of its possible application to AM-LCDs and active-matrix organic light-emitting displays     

Integrated a-Si:H Source Drivers for 4 ′′ QVGA Electrophoretic Display on Flexible Stainless Steel Substrate

Integrated source drivers for a 4' Quarter Video Graphics Array (QVGA) electrophoretic display have been developed using amorphous silicon TFTs on flexible stainless steel substrate. The current design reduces the number of column interconnects to the display by more than 3times compared to a display with external drivers. This integration reduces cost and improves reliability     

Dynamic Response of Normal and Corbino a-Si:H TFTs for AM-OLEDs

The dynamic characteristics of normal and Corbino hydrogenated amorphous silicon (a-Si:H) thin-film transistors (TFTs) have been investigated. Top- and bottom-gate normal a-Si:H TFTs and bottom-gate Corbino a-Si:H TFTs were fabricated with a five-photomask process used in the processing of the active-matrix liquid crystal displays. The charging time and feedthrough voltage $Delta V_{P}$ measurement indicates that the normal a-Si:H TFT shows a similar behavior regardless of its TFT geometrical structure. Using a simple gate-to-source capacitance $C_{rm GS}$ model, the dependence of $Delta V_{P}$ on gate-to-source overlap and storage capacitor has closely been estimated using analytical calculation. Due to a unique electrode geometry, the Corbino a-Si:H TFT shows a small deviation from an analytical model used for the normal a-Si:H TFT, and consequently, a modified analytical model was developed. We also developed concepts of its possible application as a switching device to active-matrix organic light-emitting displays.