Semiconductor device and method of manufacturing the same

Abstract

A barrier layer that meets three requirements, “withstand well against etching and protect a semiconductor film from an etchant as an etching stopper”, “allow impurities to move in itself during heat treatment for gettering”, and “have excellent reproducibility”, is formed and used to getter impurities contained in a semiconductor film. The barrier layer is a silicon oxide film and the ratio of a sub-oxide contained in the barrier layer is 18% or higher.

1 . A semiconductor device including a semiconductor layer, a gate insulating film, and a gate electrode that are formed on an insulating surface, wherein the semiconductor layer contains an element that accelerates crystallization and the concentration of the element is graded in the thickness direction of the semiconductor layer.  
   
   
       2 . A semiconductor device including a semiconductor layer; a gate insulating film, and a gate electrode that are formed on an insulating surface, 
 wherein the semiconductor layer contains an element that accelerates crystallization and the concentration of the element is graded in the thickness direction of the semiconductor layer, and    wherein the concentration of the element that accelerates crystallization is higher in the surface side of the semiconductor layer than in the substrate side of the semiconductor layer.    
   
   
       3 . A method of manufacturing a semiconductor device according to  claim 1 , wherein the element that accelerates crystallization is one or more kinds of element selected from the group consisting of Ni, Fe, Co, Sn, Pb, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au.  
   
   
       4 . A method of manufacturing a semiconductor device according to  claim 2 , wherein the element that accelerates crystallization is one or more kinds of elements selected from the group consisting of Ni, Fe, Co, Sn, Pb, Ru, Rh, Pd, Os, Ir, Pt, Cu, and Au.  
   
   
       5 . A semiconductor device according to  claim 1 , wherein the average surface roughness Ra of the surface of the semiconductor layer is 4.7 to 8.3 nm.  
   
   
       6 . A semiconductor device according to  claim 2 , wherein the average surface roughness Ra of the surface of the semiconductor layer is 4.7 to 8.3 nm.  
   
   
       7 . A semiconductor device according to  claim 1 , wherein the semiconductor device is applied to an electronic appliance selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a DVD player, a CD player, a digital camera, a front type projector, a rear type projector, a portable telephone, a portable book and a television.  
   
   
       8 . A semiconductor device according to  claim 2 , wherein the semiconductor device is applied to an electronic appliance selected from the group consisting of a personal computer, a video camera, a mobile computer, a goggle type display, a DVD player, a CD player, a digital camera, a front type projector, a rear type projector, a portable telephone, a portable book and a television.