Thin-film transistor

About: Thin-film transistor is a research topic. Over the lifetime, 48425 publications have been published within this topic receiving 680879 citations. The topic is also known as: TFT.

Switch mode power amplifier using fet with field plate extension

Abstract: Disclosed are a switch mode power amplifier and a field effect transistor especially suitable for use in a switch mode power amplifier. The transistor is preferably a compound high electron mobility transistor (HEMT) having a source terminal and a drain terminal with a gate terminal therebetween and positioned on a dielectric material. A field plate extends from the gate terminal over at least two layers of dielectric material towards the drain. The dielectric layers preferably comprise silicon oxide and silicon nitride. A third layer of silicon oxide can be provided with the layer of silicon nitride being positioned between layers of silicon oxide. Etch selectivity is utilized in etching recesses for the gate terminal.

Phase and Optical Characterizations of Annealed SnO Thin Films and Their p-Type TFT Application

Abstract: Amorphous SnO thin films were prepared on quartz and 190 nm SiO2/Si(001) substrates by electron beam evaporation. X-ray diffraction results reveal that amorphous SnO transforms into polycrystalline alpha-SnO (tetragonal litharge structure) after rapid thermal annealing in Ar ambient at 350-400 degrees C and starts decomposing into o-SnO2 (orthorhombic structure) with the expulsion of Sn atoms at 450-500 degrees C. The optical properties were characterized via spectroscopic ellipsometry. The polycrystalline SnO thin films have a higher refractive index n and a narrower bandgap E-g than the amorphous ones, which is due to the polarizability enhancement in the crystallization process. Moreover, the relationship between n and Eg of the amorphous and polycrystalline SnO thin films can be explained by the "Moss rule" law, and a decreasing trend in n was verified with the transformation from SnO to SnO2. Bottom-gate-type thin film transistors (TFTs) employing polycrystalline SnO channels on the SiO2/Si(001) substrates exhibit p-type field-effect transistor characteristics. The optimum field-effect mobilities mu(sat) and mu(lin) are 0.46 and 0.87 cm(2) V-1 s(-1), respectively, which are the same order of magnitude as those reported for epitaxial SnO TFTs. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3385390] All rights reserved.

Comparison of Ultraviolet Photo-Field Effects between Hydrogenated Amorphous Silicon and Amorphous InGaZnO4 Thin-Film Transistors

Abstract: We discuss the ultraviolet (UV) photo-field effects in amorphous InGaZnO4 thin-film transistors (a-IGZO TFTs) compared with those in hydrogenated amorphous silicon (a-Si:H) TFTs. It is shown that the UV illumination induces a much more significant threshold voltage (Vt) decrease and OFF-current increase for the a-IGZO TFTs than for the a-Si:H TFTs. The significant Vt decrease is found to take several tens of min to return to the initial state after switching off the UV light. A qualitative model is introduced to explain the photoresponse unique to the a-IGZO TFTs.

Solution-deposited Zr-doped AlOx gate dielectrics enabling high-performance flexible transparent thin film transistors

Abstract: Although high dielectric constant (k) oxide thin film has been considered as a key element for high performance and low-voltage driven thin-film transistors (TFTs), there are no solution processable high-k oxide dielectrics that satisfy the stringent requirements of low-temperature processability, mechanical flexibility, and good TFT performance. Here, we demonstrate that the incorporation of a zirconium component that has strong bonding to oxygen enables a significant reduction in the processing temperature for soluble alumina dielectrics to as low as 250 °C. Based on these Zr-AlOx films, high performance, low operational voltage, flexible TFTs are achieved. Flexible TFTs operate well under a gate bias of 5 V, exhibiting a high saturation mobility of 51 cm2 V−1 s−1, an on/off current ratio of 104, and a low threshold voltage of 1.2 V with good mechanical flexibility. This is the first study demonstrating the mechanical flexibility of all-oxide soluble high-k dielectric–semiconductor-based TFTs with an emphasis on the influence of annealing temperature on the solution-deposited high-k oxide dielectric characteristics.

High performance indium gallium zinc oxide thin film transistors fabricated on polyethylene terephthalate substrates

Abstract: High-performance amorphous (α−) InGaZnO-based thin film transistors (TFTs) were fabricated on flexible polyethylene terephthalate substrates coated with indium oxide (In2O3) films. The InGaZnO films were deposited by rf magnetron sputtering with the presence of O2 at room temperature. The n-type carrier concentration of InGaZnO film was ∼2×1017 cm−3. The bottom-gate-type TFTs with SiO2 or SiNx gate dielectric operated in enhancement mode with good electrical characteristics: saturation mobility 11.5 cm2 V−1 s−1 for SiO2 and 12.1 cm2 V−1 s−1 for SiNx gate dielectrics and drain current on-to-off ratio >105. TFTs with SiNx gate dielectric exhibited better performance than those with SiO2. This is attributed to the relatively high dielectric constant (i.e., high-k material) of SiNx. After more than 500 h aging time at room temperature, the saturation mobility of the TFTs with SiO2 gate dielectric was comparable to the as-fabricated value and the threshold voltage shift was 150 mV.