Manufacture of film semiconductor device

Abstract

The invention relates to manufacturing an excellent polycrystalline thin film semiconductor device under a comparatively lower temperature. After formation of an amorphous semiconductor film, it is crystallized in the solid phase. Thereafter, the crystallized amorphous semiconductor film is partly fused through irradiation of a pulse laser which exhibits absorption coefficient in the amorphous silicon which is higher than that in the polycrystalline silicon.

Description

technical field [0001] The present invention relates to a technique for forming an excellent polycrystalline semiconductor film with the best crystallization properties at a relatively low temperature below about 600 degrees Celsius; in particular, it relates to a manufacturing method for significantly improving the performance of semiconductor devices represented by polysilicon thin film transistors using this technique. Background technique [0002] When thin film semiconductor devices typified by polysilicon thin film transistors (p-Si TFTs) can be manufactured at low temperatures below 600 degrees Celsius using general-purpose glass substrates, the following manufacturing methods have been employed in the past. First, an amorphous silicon film to be a semiconductor film is deposited to a thickness of 50 nm on a substrate by a low-pressure chemical vapor deposition method (LPCVD method). Next, XeCl excimer laser light (wavelength: 308 nm) was irradiated on the amorphous f...

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Problems solved by technology

[0003] However, in the past manufacturing methods of thin-film semiconductor devices, the energy density of the excimer laser is difficult to control, and even if the energy density fluctuates slightly, the semiconductor film quality will show obvious deviations within the same substrate

Moreover, even if the irradiation energy density is slightly increased according to the threshold value determined by the film thickness and the corresponding hydrogen content, serious damage will occur on the semiconductor film, resulting in a significant decline in semiconductor characteristics and product yield.

In this way, in order to obtain a polycrystalline semiconductor film of uniform quality in the substrate, it is necessary to set the laser energy density at an optimum value, so in order to obtain a good polycrystalline film, the energy density is not enough.

Moreover, even if the laser is irradiated at an optimum density, it is difficult to enlarge the crystal grains constituting the polycrystalline film, and many defects remain in the film.

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