Low-temperature polycrystalline silicon thin film transistor and preparation method thereof

Abstract

The invention relates to a low-temperature polycrystalline silicon thin film transistor and a preparation method thereof. The method comprises the following steps: providing a substrate; depositing a buffering layer and a non-crystalline silicon layer on the substrate in sequence, and performing laser radiation to change the non-crystalline silicon layer into a polycrystalline silicon layer which is an active layer; depositing a first grid insulating layer, a second grid insulating layer and a first metal layer on the buffering layer and the active layer in sequence, performing high-temperature activation, and photoetching and etching the first metal layer to form a grid; depositing dielectric layers on the grid insulating layers and the grid; depositing first contact holes and second contact holes in the dielectric layers, the first grid insulating layer and the second grid insulating layer; and respectively depositing source electrodes and drain electrodes on the first contact holes and the second contact holes. The thin film transistor prepared by the method can effectively overcome the structural defects of polycrystalline silicon, and the performance of the thin film transistor can be improved.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a low-temperature polysilicon thin film transistor and a manufacturing method thereof. Background technique [0002] Thin film transistors (TFT, ThinFilmTransistor) are used as switching elements in liquid crystal display devices, which have the characteristics of low power consumption, small volume and low driving voltage, and are very suitable for display devices of computers, notebooks and other devices . In the current liquid crystal display device, the active layer of the thin film transistor mainly uses amorphous silicon (amorphous silicon, a-Si), but the mobility of the thin film transistor using amorphous silicon as the active layer is very low, and it is difficult to meet the driving requirements of the peripheral circuit. The technology of using low temperature polysilicon (LowTemperaturePoly-silicon, LTPS) instead of amorphous silicon came into being. [0003] The m...

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Problems solved by technology

However, because the dielectric layer is far away from the polysilicon, the effect of activation and hydrogenation is not ideal, which easily causes problems such as abnormal electrical properties of TFT devices.

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