Film semiconductor device and LCD

Abstract

A thin-film semiconductor device is provided including a plurality of thin-film transistors (TFT) having different driving voltages formed on an glass substrate, wherein a gate electrode electric field at each of the driving voltages of the plurality of thin-film transistors is in a range of about 1MV / cm to 2MV / cm, and a drain concentration of p-type thin-film transistors (TFT) is in a range of about 3E+19 / cm<3 >to 1E+20 / cm<3>.

Description

technical field [0001] The present invention relates to a thin film semiconductor device and a liquid crystal display (LCD), in particular, to a thin film semiconductor device and an LCD having a plurality of thin film transistors (TFTs) with different driving voltages. Background technique [0002] An image display such as an LCD or an organic EL display is used for a notebook type personal computer or a mobile terminal device such as a cell phone or a monitor of a mobile device. For example, in an active matrix type LCD, TFTs are formed of polysilicon by arranging a matrix of picture elements on a glass substrate, and the TFTs are driven by a driving circuit such as an external gate circuit or a data driver. Accordingly, the active matrix type LCD displays images thereon by controlling the alignment direction of liquid crystals. [0003] Recently, as mobile terminal devices have become smaller in size, an image display method has been developed for integrally forming a dr...

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Problems solved by technology

[0006] However, in order to form figure 1 TFT shown, it is necessary to form each gate insulating film separately for transistors including p-type and n-type having different breakdown voltages, resulting in a complicated process

In addition, if figure 1 Transistors with higher drain voltages, shown on the right, require a lightly doped drain (LDD) structure that includes a lightly doped drain region, making the process more complex

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