Amorphous oxide film used as channel layer of thin film transistor and preparation method thereof

Abstract

The invention discloses an amorphous oxide thin film serving as a thin film transistor channel layer and a preparation method of the amorphous oxide thin film serving as the film transistor channel layer. The chemical formula of the anamorphous oxide thin film is Zn4AlxSn7O1. 5x+18 (0<=x<=0.5). The preparation method includes the steps that weighed Zn(NO3)2 6H2O, Al(NO3)3 9H2O and SnCl2+NH4NO3 are respectively dissolved in a mixed solution formed by dimethoxy ethanol, acetylacetone and ammonia water so that a precursor solution can be prepared, the prepared precursor solution is stirred for 6 hours to 24 hours at the temperature ranging from the normal temperature to 50 DEG C, the prepared precursor solution is filtered and then evenly mixed according to the ratio of Zn:Al:Sn=4:x:7 (0<=x<=0.5), and ageing is performed for 4 hours to 24 hours; spinning thin film formation is performed on a substrate, annealing is performed, and the thickness of the obtained thin film ranges from 10 nm to 50 nm. The surface roughness RMS of the prepared thin film is smaller than 5 nm, the carrier concentration ranges from 1014 cm<-3> to 1017 cm<-3>, and the transmittance is larger than 80 percent. The thin film serves as the channel layer to make a thin film transistor, the threshold voltage ranges from -4 V to 3 V, and the mobility ratio ranges from 2 cm<2>V<-1>S<-1> to 10 cm<2>V<-1>S<-1>. The amorphous oxide thin film used for the thin film transistor has the advantages of being high in mobility ratio, friendly to the environment, simple in method, low in cost and the like.

Description

technical field [0001] The invention relates to an amorphous oxide thin film and a preparation method thereof, in particular to an amorphous oxide thin film used as a channel layer of a thin film transistor and a preparation method thereof. Background technique [0002] With the advent of the information age, display devices are accelerating towards flat panelization and energy saving. Among them, active array drive display devices with thin-film transistors (TFTs) as switching elements stand out among many flat panel display technologies. Naturally, TFTs are also Become one of the core technologies in the field of microelectronics, especially display engineering. TFT is a field-effect semiconductor device, including several important components such as substrate, channel layer, insulating layer, gate and source-drain electrodes, among which the performance of the channel layer and the manufacturing process are critical to the final performance of the TFT. important influen...

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Problems solved by technology

[0005] Based on these advantages of oxide semiconductor thin film applied to the channel layer of TFT, recently many research groups in my country, Japan and South Korea are working on the research of TFT with oxide semiconductor thin film as the channel layer. The current research is more mature for amorphous InGaZnO thin film is used to make channel layer TFT, but this kind of TFT contains In and Ga, two expensive rare elements, especially In, which has very few reserves on the earth, and it is an associated ore of Zn, Sn and other elements. However, it is very difficult to mine, and at present, In is widely used in transparent conductive film ITO, which accelerates the consumption of In. Some researchers predict that In resources will be exhausted in the next few decades; in addition, in the current research, as TFT The preparation methods of amorphous InGaZnO thin films used in the channel layer mostly use physical deposition methods such as magnetron sputtering, pulsed laser deposition, and molecular beam epitaxy, etc. These preparation methods are very expensive, and the industrial cost of the manufactured TFT remains high

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