Thin film semiconductor device

Abstract

A thin film semiconductor device formed on a glass substrate that can improve the working characteristics and reliability of a thin film transistor. The thin film semiconductor device has a thin film transistor 3 formed on a glass substrate 1 containing an alkali metal. The glass substrate 1 is covered with a buffer layer 2 . The thin film transistor 3 formed on this buffer layer 2 has a polycrystalline semiconductor thin film 4 as an active layer. The buffer layer 2 includes at least one silicon nitride layer, and can prevent the thin film transistor 3 from being contaminated by an alkaline metal such as Na, and has such a thickness that it can protect the thin film transistor 3 from locally concentrated alkaline metal ions ( Na + ) of the electric field generated.

Description

technical field [0001] The invention relates to a thin-film semiconductor device used as a driving substrate of an active matrix liquid crystal display or a similar structure, in particular to a thin-film semiconductor device that uses ordinary glass as a substrate and is manufactured by a low-temperature process. In particular, it also relates to techniques for preventing the harmful effects of alkali metals contained in glasses. Background technique [0002] Thin film semiconductor devices are devices in which thin film transistors are formed on insulating substrates, and they have been greatly developed in recent years because they are ideal for application to driving substrates such as active matrix liquid crystal displays. Especially when using thin-film semiconductor devices in large-area liquid crystal displays. Necessary to reduce the cost of insulating substrates, glass substrates are used instead of the relatively high quality quartz substrates used in the past. ...

AI Technical Summary

Problems solved by technology

However, this approach is not always practical because it greatly reduces the advantage of using low-cost glass substrates

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