Polysilicon thin film fabrication method

a thin film and polysilicon technology, applied in the direction of basic electric elements, electrical equipment, semiconductor devices, etc., can solve the problems of non-uniform characteristics, inability to achieve uniform grain size, and inability to accurately control the growth of grain in two or three dimensions, so as to improve the electrical characteristics of tfts, improve the uniformity of device parts of the drive circuit, and control stably

US20070065998A1Active Publication Date: 2007-03-22NAT TAIWAN UNIV
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Patent Information

Authority / Receiving Office
US · United States
Patent Type
Applications(United States)
Current Assignee / Owner
Publication Date
2007-03-22

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Abstract

A polysilicon thin film fabrication method is provided, in which a heat-absorbing layer is used to provide sufficient heat for grain growth of an amorphous silicon thin film, and an insulating layer is used to isolate the heat-absorbing layer and the amorphous silicon thin film. A regular heat-conducting layer is used as a cooling source to control the crystallization position and grain size of the amorphous silicon thin film. Therefore, the amorphous silicon thin film can crystallize into a uniform polysilicon thin film, and the electrical characteristics of the polysilicon thin film can be stably controlled.
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Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a polysilicon thin film fabrication method and, more particularly, to a polysilicon thin film fabrication method capable of enhancing the uniformity of grain.

[0003] 2. Description of Related Art

[0004] The low temperature poly Si (LTPS) thin film transistor (TFT) technology will be used in future active matrix LCDs and OLEDs. Although today's LTPS TFTs have good electrical properties, they have the problem of nonuniform characteristics. In order to improve the nonuniform situation of polysilicon thin film between channels, it is necessary to control the size and distributed distance of polysilicon grains.

[0005] In 2000, Seoul University of South Korea has proposed a polysilicon thin film fabrication method, in which the high reflectivity of aluminum is used as a metallic cooling source for sideward growth. As shown in FIGS. 1A-1C, an amorphous silicon thin film 11 of a thickness of...

Examples

Embodiment Construction

[0020] As shown in FIG. 4, the present invention provides a polysilicon thin film fabrication method, which comprises the following steps.

[0021] First, a substrate is provided (Step S100). The substrate is a glass substrate, an insulator substrate, or a semiconductor substrate. Next, a heat-absorbing layer is formed on the substrate (Step S200). An insulating layer is then formed on the heat-absorbing layer (Step S300). Subsequently, an amorphous silicon thin film is formed on the insulating layer (Step S400). A regular heat-conducting layer is formed on the amorphous silicon thin film (Step S500). Finally, An annealing process is performed to let the amorphous silicon thin film crystallize with the heat-conducting layer as the center and grow outwards to form a uniform polysilicon thin film.

[0022] The present invention will be exemplified below with reference to FIGS. 5A-5H and FIGS. 6A-6C. The polysilicon thin film fabrication method of the present invention comprises the follow...