Fabricating method of low temperature poly-silicon film and low temperature poly-silicon thin film transistor

Abstract

A fabricating method of low temperature poly-silicon film is described. An amorphous silicon layer is formed on a substrate first; then, an anneal treatment is performed on the amorphous silicon layer for forming a poly-silicon layer (poly-silicon film) from the amorphous silicon layer. Several mounds are formed on the surface of the poly-silicon layer. A surface treatment step is performed;, then, another laser anneal step is conducted on the poly-silicon layer. Since the size of these mounds on the surface of the poly-silicon layer can be reduced, the issue that the mounds are too big and have different sizes in the prior art can be resolved.

1 . A fabricating method of a low temperature poly-silicon film, comprising: 
 forming an amorphous silicon layer on a substrate;    performing a first anneal treatment on the amorphous silicon layer, so as to covert the amorphous silicon layer into a poly-silicon layer wherein a plurality of mounds are formed on a surface of the poly-silicon layer, and an oxide layer is formed on the surface of the poly-silicon layer;    performing a surface treatment step on the poly-silicon layer, so as to remove the oxide layer; and    performing a second anneal treatment on the poly-silicon layer.    
   
   
       2 . The fabricating method of the low temperature poly-silicon film of  claim 1  wherein the surface treatment step is an etching treatment step.  
   
   
       3 . The fabricating method of the low temperature poly-silicon film of  claim 2  wherein the etching treatment step is performed by using a hydrofluoric acid solution.  
   
   
       4 . The fabricating method of the low temperature poly-silicon film of  claim 3  wherein the concentration of the hydrofluoric acid solution is from 1% to 15%, and the duration for performing the etching treatment step is from 1 minute to 15 minutes.  
   
   
       5 . The fabricating method of the low temperature poly-silicon film of  claim 1  wherein after the second anneal treatment is completed, the height/width ratio of the mounds on the surface of the poly-silicon layer is less than 0.2.  
   
   
       6 . The fabricating method of the low temperature poly-silicon film of  claim 1  wherein the first anneal treatment is a laser anneal treatment.  
   
   
       7 . The fabricating method of the low temperature poly-silicon film of  claim 1  wherein the second anneal treatment is a laser anneal treatment.  
   
   
       8 . The fabricating method of the low temperature poly-silicon film of  claim 1  further comprising a step of forming a buffer layer on the substrate before the amorphous silicon layer is formed on the substrate.  
   
   
       9 - 10 . (canceled)