Thin film transistor and its manufacturing method

Abstract

The invention relates to a thin film transistor and a manufacturing method thereof. The manufacturing method includes the following steps: depositing a gate metal film on a substrate, and obtaining agate pattern through a first composition process; and sequentially depositing a gate insulating film, a semiconductor film, a doped semiconductor film and a source-drain metal film on the substrate onwhich the gate pattern is formed, and obtaining a channel region and source and drain patterns through a second composition process, wherein the step of depositing the source-drain metal film on thedoped semiconductor film includes the depositing of a first metal molybdenum film, a metal aluminum film and a second metal molybdenum film on the doped semiconductor film in turn. The problem that the doped semiconductor layer has a protruding part relative to the source-drain metal layer due to the over-etching of the source-drain metal film in the second composition process and thus the performance of the thin film transistor is reduced is solved.

Description

technical field [0001] The invention relates to the technical field of liquid crystal display, in particular to a thin film transistor and a manufacturing method thereof. Background technique [0002] In the manufacturing process of thin film transistors, four photolithography processes are usually used. In the process of obtaining the channel region, source and drain patterns in the second photolithography process, two dry etching and two wet etching processes are usually required. Due to the different process characteristics of dry etching and wet etching, it is easy to cause over-etching of the metal film of the source and drain during etching, so that the protrusions of the semiconductor layer and the doped semiconductor layer relative to the source and drain are longer , affecting the electrical properties of thin film transistors. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a thin film transistor capab...

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Problems solved by technology

[0002] In the manufacturing process of thin film transistors, four photolithography processes are usually used. In the process of obtaining the channel region, source and drain patterns in the second photolithography process, two dry etching and two wet etching processes are usually required. Due to the different process characteristics of dry etching and wet etching, it is easy to cause over-etching of the metal film of the source and drain during etching, so that the protrusions of the semiconductor layer and the doped semiconductor layer relative to the source and drain are longer , affecting the electrical properties of thin film transistors

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