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We propose and demonstrate self-aligned Double Injection Function Thin Film Transistor (DIF-TFT) architecture that mitigates short channel effects in 200 nm channel on non-scaled insulator (100 nm SiO₂). In this conceptual design, a combination of ohmic-like injection contact and a high injection-barrier metal allows maintaining the high on current...
Contexts in source publication
Context 1
... set the scene, we show in Fig. 7 a cross-section SEM-FIB image focused on the right side of the symmetric design presented as an inset (Fig. 4). The FIB image shows the IGZO film on top of the Si/SiO 2 substrate. The source M1 metal is a 25 nm-thick molybdenum (Mo), and M2 is a 35 nm thick platinum (Pt). Lastly, the source dielectric is 400 nm Al 2 O 3 , and the top ...
Context 2
... a combination of platinum on molybdenum source metal was fabricated in the proposed configuration ( Fig. 7) with the same IGZO solution thickness and atom ratio. After detailed analysis using experiments and simulations, we concluded that when we deposit on the IGZO four different materials (molybdenum, platinum, alumina, and silver), we lose our ability to control the oxygen vacancies concentration in the IGZO film. As the entire DWF source ...
Citations
... [14][15][16][17] To meet the demand of display application, the relatively low I dsat in MO SBTFTs based on single-metal-layer S/D electrodes are also improved by using stacked S/D electrodes with different work functions. 16,18 Despite of these progresses, the electrical properties of MO SBTFTs, such as I dsat and V dsat , often vary notably when the devices employ different S/D electrodes and MO semiconductors. It is well known that the I dsat of the devices is determined by the contact resistance and channel resistance of the devices. ...
In this work, we performed systematic electrical characterization and analysis of indium–gallium–zinc oxide (IGZO) Schottky-barrier thin-film transistors (SBTFTs) with different Cu-based Schottky contact structures. It was found that the Schottky barrier height (ΦB) between the IGZO layer and the Cu electrode could be modulated notably by changing the thickness of the AlOx tunnel layer, and the variation in ΦB significantly changed the saturation drain current (Idsat) of the IGZO SBTFTs based on the Schottky contacts but only had a minor influence on the saturation voltage (Vdsat) of the devices. Furthermore, Cu/Al stacked source/drain electrodes and silicon nitride (SiNx) passivation were employed to tailor the contact resistance and channel resistance of the IGZO SBTFTs, which led to an increase in Idsat and a variation in Vdsat. A universal resistance–capacitance network model was proposed to explain the observed evolution of Vdsat of the SBTFTs with different device structures. This work provides meaningful insight into developing low-cost metal oxide SBTFTs with tailored device performances.
... However, one cannot adopt the solutions developed for the silicon industry and alternative approaches are being developed. [6][7][8][9] The Schottky contact TFT architecture, known as the source gated transistor (SGT), has been around for at least 20 years [10][11][12] and has gained renewed interest. This renewed interest is mainly due to works like Shannon et al. 13 that brought the context of Schottky contacts to short channel (lateral) transistors, keeping the output conductance low. ...
... In a recent publication, 8 we fabricated self-aligned InGaZnO (IGZO) based source controlled TFTs (SCT-TFT) to demonstrate that the penalty in ON current could be circumvented. The concept was to separate the two functions of the source, i.e., of charge injection and depletion [ Fig. 1(b)]. ...
... Namely, to realize DIFT, we used a double work function (DWF) source electrode, where for the IGZO TFTs, we used molybdenum and platinum as Ohmic and Schottky contacts, respectively. 8 In this different design, the source is not gating the transistor but is only controlling the physical path of the current while screening the effect of the drain bias (field). ...
Metal oxide-based electronics is advancing rapidly where the reduced dimensions require transistor structures different to conventional CPUs. The double injection function transistor (DIFT) is a type of a source-controlled transistor. As doping is a facile method in the semiconductor industry, we suggest that the DIFT can be realized through a doping pattern under the source electrode. We show that double doping functions similarly to the double work function DIFT, recently demonstrated. We use device simulations to analyze the operation principle of the DIFT structure and provide design guidelines. We find that the structural separation of the injection and depletion functions allows adapting the transistor structure to fabrication process limitations. A 200 nm channel length InGaZnO based device can be designed to exhibit proper saturation at sub-1 V drain bias.
Changes in the electrical properties and trap characteristics of flexible low-temperature polysilicon thin-film transistors (TFTs) under the application of uniaxial bending strains and during repetitive bending cycles were investigated. When the bending strain increased, the transfer curve showed a negative shift, the output current decreased, and the subthreshold slope increased. After the bending strains were removed, the electrical performance showed recovery behavior, but the device performance could not return fully to its original state. The devices were also subjected to repetitive bending cycles. The transfer curves showed a positive shift after 10
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bending cycles and the output current increased. Using the transient current method, it was established that the detrapping time constant of the traps decreased and the peak amplitudes increased as a result of both the bending strain and the bending cycles. However, while the trap activation energy was not changed by static bending, it did decrease after the repetitive bending cycles. Both the changes in the electrical properties and the time constant spectra confirm that the trap state density increased as a result of the bending processes. However, the different trapping behaviors contributed to different degradations in the device’s electrical properties.
