Thin film transistor low-temperature polycrystalline silicon thin film manufacturing method

Abstract

The invention discloses a thin film transistor low-temperature polycrystalline silicon thin film manufacturing method. The method includes the steps of firstly, sequentially depositing an isolation layer, a non-crystalline silicon layer and an anti-reflection heat preservation layer on a glass substrate where a TFT metal grid is plated in advance; secondly, coating the anti-reflection heat preservation layer with photoresist through a picture composition process, and conducting mask exposure and developing through the TFT metal grid; thirdly, etching the portion, in a non-channel area, of the anti-reflection heat preservation layer, and conducting demolding on the photoresist; fourthly, conducting laser radiation so that the non-crystalline silicon of a channel area can be converted into large-size polycrystalline silicon. By means of the technical scheme, the temperature gradient of the TFT channel area and the non-channel area can be formed, the manual-control super transverse growth of crystalline grain from the non-channel area to the channel area can be achieved, the TFT channel area has only one grain boundary, and therefore the carrier migration rate is increased, and the performance of a device in a channel is uniform.

Description

technical field [0001] The invention relates to the technical field of semiconductor device preparation, in particular to a method for preparing a low-temperature polysilicon film for a thin film transistor. Background technique [0002] Polycrystalline silicon (p-Si) thin film has a high carrier mobility much larger than that of amorphous silicon (a-Si) and comparable to that of single crystal silicon, and is often used in active TFT (Thin Film Transistor) Layers, for example, have very important applications in active liquid crystal displays (AMOLCDs) and active organic light emitting diodes (AMOLEDs). [0003] The substrate of the polysilicon thin film of the flat panel display is usually glass which cannot withstand the high temperature process. Under the limitation of this condition, the industry must choose to develop the low temperature polysilicon (LTPS) technology. In research, the inventors found that the low-temperature polysilicon film used in the traditional te...

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Problems solved by technology

The inventor found in the research that the number of grain boundaries contained in the TFT channel is different when the low-temperature polysilicon film is used in the traditional technology, which will cause the problem of uneven device performance, and its carrier mobility can be further improved

To solve this problem, of course, monocrystalline silicon thin films can be used to replace polycrystalline silicon thin films, but this will increase the cost of flat panel display manufacturing

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