Patent Application
20070262379
1. Field of the Invention
The invention relates to a thin film transistor and manufacturing, more especially, to a thin film transistor forming on a silicon nitride surface of glass substrate and the silicon nitride surface formation.
2. Background of the Related Art
Thin film transistor is a main technology in the thin film transistor liquid crystal display.
The replacement of aluminum is one of silver, copper, copper alloy and silver alloy, but they do not easily adhere to the glass substrate. To enhance the adhesion is to form molybdenum layer on the glass substrate, and subsequently forms a copper layer on the molybdenum layer.
How to treat the surface of the glass substrate to enhance the adhesion copper, silver or alloy of copper and silver is an important technology.
One of objects of this invention is to enhance the adhesion between one of copper, silver, copper alloy and silver alloy. The technology is to form a silicon nitride layer on the glass substrate surface, and to plate with one of copper, silver, copper alloy and silver alloy to form a metallic layer on the silicon nitride layer, and subsequently to form the pattern of thin film transistor, and finally to complete the thin film transistor.
Another one of objects of this invention is to invert into silicon nitride on the glass substrate surface. The technology is to replace oxygen atom in the silicon oxide on the glass substrate surface with nitrogen atom to form a silicon nitride layer. The silicon nitride layer isolates and avoids one of copper ion and silver ion diffusing into the glass substrate.
According to the mentioned above, etching the metallic layer on glass substrate surface draws the gate electrode of thin film transistor, and subsequently forms the thin film transistor by conventional semiconductor process. It means to etch the metallic layer to form the gate electrode, and to cover the gate electrode with an isolative layer, semi conductive layer, and two discrete doping layers covered by metallic contacts as the electrodes, and to complete the thin film transistor.
Step 710 is to invert the surface of the glass substrate into a silicon nitride layer. To replace oxygen of the silicon oxide with nitrogen forms the silicon nitride layer on the glass substrate surface by plasma treatment or ion implementation by leading gases including the nitrogen, like ammonia, mixture of hydrogen and nitrogen or mixture of hydrogen and ammonia.
Step 720 is to form the metallic layer on the silicon nitride layer. Low resistance metal, like copper, silver, copper alloy and silver alloy, constructs the metallic layer, and the physical vapor deposition (noted PVD), metal organic chemical vapor deposition (MOCVD) or printing is employed.
Step 711 is to invert the surface of the glass substrate into a silicon layer. The method is the plasma treatment or the ion implementation leading the gases including hydrogen, like hydrogen gases, mixture of hydrogen and nitrogen or mixture of hydrogen and ammonia to take the oxygen away from silicon oxide of the glass substrate.
Step 712 is to invert the silicon layer into a silicon nitride layer. The method is also the plasma treatment or the ion implementation leading the gases including nitrogen, like ammonia, mixture of hydrogen and nitrogen or mixture of hydrogen and ammonia.
Step 721 is to form the metallic layer on the silicon nitride layer. Low resistance metal, like copper, silver, copper ally and silver alloy, constructs the metallic layer, and the physical vapor deposition (PVD), metal organic chemical vapor deposition (MOCVD) or printing is employed.
Thin film transistor forms on the metallic layer by etching the metallic layer into the gate electrode of the thin film transistor.
Step 810 is to invert the surface of the glass substrate into a silicon nitride layer. To replace oxygen of the silicon oxide with nitrogen forms the silicon nitride layer on the glass substrate surface by plasma treatment or ion implementation by leading gases including the nitrogen, like ammonia, mixture of hydrogen and nitrogen or mixture of hydrogen and ammonia.
Step 820 is to form the metallic layer on the silicon nitride layer. Low resistance metal, like copper, silver, copper alloy and silver alloy, constructs the metallic layer, and the physical vapor deposition (PVD), metal organic chemical vapor deposition (MOCVD) or printing is employed.
Step 830 is to draw the gate electrode according to the designed pattern, and in generally the method is the wet etching.
Step 840 is to form the isolative layer covering the gate electrode, and the layer would avoid electrical leakage.
Step 850 is to complete the manufacturing thin film transistor, that is, to stack and/or etch the rest layers of a thin film transistor, that is, to form the semi-conductive layer on the isolative layer, and to form two discrete doped layers covered by metallic electrodes as the source and drain electrode. In generally the doped layers are doped by the phosphor.
Basically the step 810 may be divided to two steps, first is to invert the silicon oxide into silicon layer and subsequently to silicon nitride layer.
Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that other modifications and variation can be made without departing the spirit and scope of the invention as claimed.
