Zinc-oxide-base amorphous oxide semiconductor thin film transistor and manufacturing method thereof

Abstract

The invention discloses a zinc-oxide-base amorphous oxide semiconductor thin film transistor and a manufacturing method of the zinc-oxide-base amorphous oxide semiconductor thin film transistor. The zinc-oxide-base amorphous oxide semiconductor thin film transistor comprises a substrate, a grid electrode, a grid insulating layer, an active layer, a source electrode and a drain electrode, wherein the grid electrode is formed on the substrate, the grid electrode and the substrate are covered with the grid insulating layer, the active layer is formed on the grid insulating layer and corresponds to the grid electrode, and the two ends of the active layer are covered with the source electrode and the drain electrode respectively; a zinc-oxide-base amorphous oxide semiconductor doped with X and Y serves as the active layer, when the distance between the active layer and the grid insulating layer gradually increases, the content of the X gradually decreases, and the content of the Y gradually increases; the X is one of Cd, In, Sn, Sb, Ti, Pb and As, and the Y is one of Ga, Al, Hf, Ge, Ca and Cu. According to the zinc-oxide-base amorphous oxide semiconductor thin film transistor and the manufacturing method of the zinc-oxide-base amorphous oxide semiconductor thin film transistor, the mobility ratio of a device can be effectively improved, the magnitude of the working current of the device can be effectively improved, the frequency of the phenomenon of threshold voltage drift of the device is reduced, influence of the technology, illumination and gas in the outside world on the device is reduced, and mechanical stability of the device is improved.

Description

technical field [0001] The invention belongs to the technical field of flat panel display driving, and more specifically relates to a zinc oxide-based amorphous oxide semiconductor thin film transistor and a manufacturing method thereof. Background technique [0002] With the development of flat panel display technology, traditional silicon-based thin film transistors cannot meet the driving requirements of displays. For this reason, a thin film transistor using an amorphous metal oxide as an active layer has been proposed, which has the advantages of transparency, high mobility, and good uniformity. [0003] Since it is difficult for an amorphous metal oxide thin film transistor with a single active layer structure to balance high mobility and high electrical stability, in order to improve its electrical performance, some researchers have proposed a double-layer active layer structure. For example, using an indium tin oxide / indium gallium zinc oxide (ITO / IGZO) double-layer...

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Problems solved by technology

[0004] Nevertheless, the double-layer active layer structure has the following problems: (1) The mismatch of crystal lattice and bandwidth leads to a large number of defect states near the interface of the double-layer active layer. Factors such as the defect state of the gate insulating layer and the charge trap at the interface between the insulating layer and the active layer, and photogenerated carriers will cause the threshold voltage of the device to drift, so that the display circuit cannot work normally, and the electrical stability of the device is not high.

(2) In terms of flexible display applications, if a double-layer active layer structure is used, when the device is bent and twisted, due to the lattice mismatch of the two-layer structure, the interface will generate a large stress, resulting in a large number of defects in some areas , and even cause the device to fail to work

(3) Due to the reflection of the interface, the light transmission of the double-layer active layer structure will be affected

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