JPH07273332A - Thin film transistor - Google Patents

Abstract

PURPOSE:To surely peel a gate electrode and a gate insulation film by improving adhesion between a surface of a substrate and a gate electrode and a gate insulation film formed in a surface of the substrate. CONSTITUTION:In a thin film transistor wherein a gate electrode 2, a gate insulation film 3, semiconductor films 4, 5 and source and drain electrodes 6, 7, are deposited, the surface of the substrate 1 is subjected to and the gate electrode 2 and the gate insulation film 3 are formed in a surface 1 of the substrate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor used for a liquid crystal display device or the like.

[0002]

2. Description of the Related Art For example, a thin film transistor used as an active element of an active matrix liquid crystal display element is
A gate electrode and a gate insulating film covering the gate electrode are formed on an insulating transparent substrate made of glass or the like, and an i-type semiconductor film made of a-Si (amorphous silicon) is further formed on the gate insulating film. Do this i
A source electrode and a drain electrode are formed on the type semiconductor film via an n-type semiconductor film made of a-Si doped with impurities.

[0003]

However, the surface of the substrate made of glass or the like is in a mirror-like smooth state, so that the surface of this substrate and the gate electrode and gate insulation formed on the surface of this substrate are formed. Since the adhesion to the film is weak, the gate electrode and the gate insulating film are easily peeled off from the surface of the substrate, which causes a reduction in manufacturing yield.

The present invention has been made by paying attention to such a point, and its purpose is to improve the adhesion between the surface of the substrate and the gate electrode and the gate insulating film formed on the surface of the substrate. Another object of the present invention is to provide a thin film transistor which can surely prevent peeling of a gate electrode and a gate insulating film.

[0005]

In order to achieve such an object, the present invention provides a thin film transistor in which a gate electrode, a gate insulating film, a semiconductor film, a source and a drain electrode are formed on a substrate. The surface of the substrate is roughened, and the gate electrode and the gate insulating film are formed on the surface of the substrate.

[0006]

In such a thin film transistor, since the surface of the substrate is in a finely concavo-convex state, the contact area between the gate electrode and the gate insulating film formed on the surface and the surface of the substrate is increased, so that the gate electrode and the gate are formed. Adhesion of the insulating film is improved, and its peeling is surely prevented.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional structure of a thin film transistor. Reference numeral 1 is an insulating substrate made of glass or the like, and a gate electrode 2, a gate insulating film 3 made of SiN (silicon nitride) or the like for covering the gate electrode 2, and the gate insulating film are provided on the substrate 1. 3, an i-type semiconductor film 4 made of a-Si (amorphous silicon) arranged to face the gate electrode 2, and an n-type made of a-Si doped with impurities on the i-type semiconductor film 4. Source electrode 6 and drain electrode 7 formed via the semiconductor film 5
And are formed.

A blocking film 8 protects the channel region of the i-type semiconductor film 4 during etching. The surface of the substrate 1 is subjected to a surface roughening treatment a, and the surface of the substrate 1 has fine irregularities by the surface roughening treatment a, and the gate electrode 2 and the gate insulating film 3 are formed on the surface of the substrate 1. Are formed.

The roughening treatment a of the surface of the substrate 1 is, for example, A
r Plasma etching or a method of spraying an acidic liquid or an alkaline liquid capable of dissolving the substrate 1 onto the surface of the substrate 1 in a shower shape.

In the thin film transistor having such a structure, the surface of the substrate 1 is subjected to a surface roughening treatment a in the form of fine irregularities, and therefore the gate electrode 2 and the gate insulating film 3 formed on the surface are treated. The contact area with the surface of the substrate 1 is increased, and the gate electrode 2 and the gate insulating film 3 are firmly and firmly attached to the surface of the substrate 1. Therefore, peeling of the gate electrode 2 and the gate insulating film 3 from the surface of the substrate 1 is reliably prevented, and the manufacturing yield is improved.

[0011]

As described above, according to the present invention, the surface of the substrate is roughened and the gate electrode and the gate insulating film are formed on the surface of the substrate. Adhesion with the gate electrode and the gate insulating film can be improved, and peeling of the gate electrode and the gate insulating film from the surface of the substrate can be reliably prevented, and the manufacturing yield can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a thin film transistor showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... Gate electrode 3 ... Gate insulating film 4 ... i-type semiconductor film 5 ... N-type semiconductor film 6 ... Source electrode 7 ... Drain electrode a ... Roughening treatment

Claims (1)

[Claims] 1. A gate electrode, a gate insulating film, and
In a thin film transistor having a semiconductor film, source and drain electrodes formed, the surface of the substrate is subjected to a surface roughening treatment, and the gate electrode and the gate insulating film are formed on the surface of the substrate. Thin film transistor.