scholarly journals Demonstration on Ferroelectric-gate Thin Film Transistor NAND-type Array with Disturbance-free Operation

Author(s):  
Bui Nguyen Quoc Trinh

Abstract: A novel concept of NAND memory array has been proposed by using only ferroelectric-gate thin film transistors (FGTs), whose structure is constructed from a sol-gel ITO channel and a sol-gel stacked ferroelectric between Bi3.25La0.75Ti3O12 and PbZr0.52TiO0.48O3 (BLT/PZT) gate insulator. Interestingly, ferroelectric cells with a wide memory window of 3 V and a large on/off current ratio of 6 orders, have been successfully integrated in a NAND memory circuit. To protect data writing or reading from disturbance, ferroelectric transistor cells are directly used, instead of paraelectric transistor cells as usual. As a result, we have verified disturbance-free operation for data reading and writing, with a small loss of the memory state and a low power consumption, in principle. Keywords: ITO, PZT, NAND, FeRAM, ferroelectric.

2007 ◽  
Vol 997 ◽  
Author(s):  
Eisuke Tokumitsu ◽  
Masaru Senoo ◽  
Etsu Shin ◽  
Tomofumi Fujimura

AbstractIndium tin oxide (ITO)-channel ferroelectric-gate thin film transistor (TFT) with large on/off current ratio is demonstrated by using mechanical polishing process to planarize the surface of ferroelectric bottom gate insulator (Bi,La)4Ti3O12 (BLT). It is shown that the mechanical polishing of the sol-gel derived polycrystalline ferroelectric BLT films causes no degradation in electrical properties. ITO channel layer was then deposited on the planarized BLT gate insulator to fabricate ferroelectric-gate TFTs. The off-current of the ITO/BLT TFT fabricated with the polishing process is drastically reduced to around 10−12 A, which is four orders of magnitude lower than that of the TFT fabricated without the polishing process. The obtained on/off current ratio is more than 107. In addition, a subthreshold voltage swing as small as 200 mV/decade was obtained.


Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 200
Author(s):  
Do Won Kim ◽  
Hyeon Joong Kim ◽  
Changmin Lee ◽  
Kyoungdu Kim ◽  
Jin-Hyuk Bae ◽  
...  

Sol-gel processed SnO2 thin-film transistors (TFTs) were fabricated on SiO2/p+ Si substrates. The SnO2 active channel layer was deposited by the sol-gel spin coating method. Precursor concentration influenced the film thickness and surface roughness. As the concentration of the precursor was increased, the deposited films were thicker and smoother. The device performance was influenced by the thickness and roughness of the SnO2 active channel layer. Decreased precursor concentration resulted in a fabricated device with lower field-effect mobility, larger subthreshold swing (SS), and increased threshold voltage (Vth), originating from the lower free carrier concentration and increase in trap sites. The fabricated SnO2 TFTs, with an optimized 0.030 M precursor, had a field-effect mobility of 9.38 cm2/Vs, an SS of 1.99, an Ion/Ioff value of ~4.0 × 107, and showed enhancement mode operation and positive Vth, equal to 9.83 V.


Electronics ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 1099
Author(s):  
Ye-Ji Han ◽  
Se Hyeong Lee ◽  
So-Young Bak ◽  
Tae-Hee Han ◽  
Sangwoo Kim ◽  
...  

Conventional sol-gel solutions have received significant attention in thin-film transistor (TFT) manufacturing because of their advantages such as simple processing, large-scale applicability, and low cost. However, conventional sol-gel processed zinc tin oxide (ZTO) TFTs have a thermal limitation in that they require high annealing temperatures of more than 500 °C, which are incompatible with most flexible plastic substrates. In this study, to overcome the thermal limitation of conventional sol-gel processed ZTO TFTs, we demonstrated a ZTO TFT that was fabricated at low annealing temperatures of 350 °C using self-combustion. The optimized device exhibited satisfactory performance, with μsat of 4.72 cm2/V∙s, Vth of −1.28 V, SS of 0.86 V/decade, and ION/OFF of 1.70 × 106 at a low annealing temperature of 350 °C for one hour. To compare a conventional sol-gel processed ZTO TFT with the optimized device, thermogravimetric and differential thermal analyses (TG-DTA) and X-ray photoelectron spectroscopy (XPS) were implemented.


2021 ◽  
Vol 23 (09) ◽  
pp. 1078-1085
Author(s):  
A. Kanni Raj ◽  

Indium Lead Oxide (ILO) based Metal Oxide Thin Film Transistor (MOTFT) is fabricated with Lead Barium Zirconate (PBZ) gate dielectric. PBZ is formed over doped silicon substrate by cheap sol-gel process. Thin film PBZ is analysed with X-ray Diffraction (XRD), Ultra-Violet Visible Spectra (UV-Vis) and Atomic Force Microscope (AFM). IZO is used as bottom gate to contact Thin Film Transistor (TFT). This device needs only 5V as operating voltage, and so is good for lower electronics <40V. It shows excellent emobility 4.5cm2/V/s, with on/off ratio 5×105 and sub-threshold swing 0.35V/decade.


Materials ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 137 ◽  
Author(s):  
Seung-Hun Lee ◽  
Kihwan Kwon ◽  
Kwanoh Kim ◽  
Jae Sung Yoon ◽  
Doo-Sun Choi ◽  
...  

The properties of Al-doped SnOx films deposited via reactive co-sputtering were examined in terms of their potential applications for the fabrication of transparent and flexible electronic devices. Al 2.2-atom %-doped SnOx thin-film transistors (TFTs) exhibit improved semiconductor characteristics compared to non-doped films, with a lower sub-threshold swing of ~0.68 Vdec−1, increased on/off current ratio of ~8 × 107, threshold voltage (Vth) near 0 V, and markedly reduced (by 81%) Vth instability in air, attributable to the decrease in oxygen vacancy defects induced by the strong oxidizing potential of Al. Al-doped SnOx films maintain amorphous crystallinity, an optical transmittance of ~97%, and an adhesive strength (to a plastic substrate) of over 0.7 kgf/mm; such films are thus promising semiconductor candidates for fabrication of transparent flexible TFTs.


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