Method for forming polycrystalline series film layer by utilizing laser crystallization

Abstract

This invention provides a polycrystalline film method by use of laser crystallization, which forms a film of non-crystal film with certain thickness from the edge to the side of the base plate through controlling gas concentration distribution in the deposit reaction chamber and makes the laser annealing of the non-crystal film to turn it into polycrystalline film.

Description

technical field [0001] The present invention relates to a method for forming a film layer by laser crystallization, in particular to the utilization of a continuous lateral solidification (sequential lateral solidification; SLS) process (low temperature poly silicon process; LTPS process) Laser crystallization is a method of forming a polycrystalline film layer. Background technique [0002] Thin film transistors are active elements commonly used in active matrix flat panel displays, and are usually used to drive active matrix type liquid crystal displays, active matrix type organic light-emitting displays, etc. device. Semiconductor silicon films in thin film transistors can generally be classified into polysilicon (poly-silicon) films and amorphous silicon (a-Si:H) films. [0003] Although amorphous silicon thin film has the advantages of low processing temperature, suitable for mass production because it can be prepared by vapor phase deposition, and relatively mature p...

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Problems solved by technology

However, the above-mentioned method has the following defects. The defect of the first method is that the polysilicon film must be deposited thick enough to form a large grain, and its surface uniformity is poor, and the required processing temperature is also up to 600 degrees.

Although the second method can produce a thin and uniform polysilicon film, the temperature required for the crystallization step is as high as 600 degrees, the thermal budget is high, and the time required is long, which will affect the yield.

The third method has a low processing temperature. It is known that the method of excimer laser annealing (ELA) converts amorphous silicon into polysilicon, but the scanning speed is about 0.2mm / sec, and the energy is about 370mJ / cm 2 , not only the yield is low, limited by the size of the energy, the crystallization often only occurs on the surface, and the purpose of recrystallizing the entire layer of amorphous silicon into polysilicon cannot be achieved.

As shown in Figure 1, the opening point of the shutter is set to be D and E, but the fully opening point of the shutter is d and e, so the laser energy received by the amorphous silicon thin film 14 of a section will be uneven, which reduces the available laser energy on the contrary. The area where the panel is made

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