Semiconductor device and manufacturing method thereof

Abstract

An object is to provide a transistor including an oxide semiconductor having favorable electrical characteristics and a manufacturing method thereof. A semiconductor device includes an oxide semiconductor film and an insulating film over a substrate. An end portion of the oxide semiconductor film is in contact with the insulating film. The oxide semiconductor film includes a channel formation region and regions containing a dopant between which the channel formation region is sandwiched. The semiconductor device further includes a gate insulating film over and in contact with the oxide semiconductor film, a gate electrode with a sidewall insulating film over the gate insulating film, and a source electrode and a drain electrode in contact with the sidewall insulating film, the oxide semiconductor film, and the insulating film.

1 . A semiconductor device comprising:
 an oxide semiconductor film;   an insulating film in contact with a side surface of the oxide semiconductor film;   a gate insulating film over the oxide semiconductor film; and   a gate electrode over the gate insulating film.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein the insulating film is formed using aluminum oxide. 
     
     
         3 . The semiconductor device according to  claim 1 , wherein the oxide semiconductor film is formed using a metal oxide containing at least one element selected from In, Ga, Sn, and Zn. 
     
     
         4 . A semiconductor device comprising:
 a first insulating film comprising a protrusion;   an oxide semiconductor film over the protrusion;   a second insulating film over the first insulating film, the second insulating film being in contact with a side surface of the oxide semiconductor film;   a gate insulating film over the oxide semiconductor film; and   a gate electrode over the gate insulating film.   
     
     
         5 . The semiconductor device according to  claim 4 , wherein the second insulating film is formed using aluminum oxide. 
     
     
         6 . The semiconductor device according to  claim 4 , wherein the oxide semiconductor film is formed using a metal oxide containing at least one element selected from In, Ga, Sn, and Zn. 
     
     
         7 . The semiconductor device according to  claim 4 , wherein the first insulating film is formed using at least one of silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxynitride, gallium oxide, hafnium oxide, and yttrium oxide. 
     
     
         8 . A semiconductor device comprising:
 a first insulating film comprising a protrusion;   an oxide semiconductor film over the protrusion, the oxide semiconductor film comprising a first region containing a dopant at a first concentration and a second region containing the dopant at a second concentration;   a second insulating film over the first insulating film, the second insulating film being in contact with a side surface of the oxide semiconductor film;   a gate insulating film over the oxide semiconductor film;   a gate electrode over the gate insulating film;   a sidewall insulating film on a side surface of the gate electrode; and   a source electrode and a drain electrode in contact with the second insulating film, the second region, and the sidewall insulating film.   
     
     
         9 . The semiconductor device according to  claim 8 , wherein the second insulating film is formed using aluminum oxide. 
     
     
         10 . The semiconductor device according to  claim 8 , wherein the oxide semiconductor film is formed using a metal oxide containing at least one element selected from In, Ga, Sn, and Zn. 
     
     
         11 . The semiconductor device according to  claim 8 , wherein the first insulating film is formed using at least one of silicon oxide, silicon oxynitride, silicon nitride oxide, aluminum oxynitride, gallium oxide, hafnium oxide, and yttrium oxide. 
     
     
         12 . The semiconductor device according to  claim 8 , wherein the first concentration of the dopant in the first region containing the dopant is lower than the second concentration of the dopant in the second region containing the dopant. 
     
     
         13 . The semiconductor device according to  claim 8 ,
 wherein the source electrode or the drain electrode comprises a first conductive film and a second conductive film, and   wherein the first conductive film is in contact with the sidewall insulating film.   
     
     
         14 . The semiconductor device according to  claim 13 , wherein the first conductive film is thinner than the second conductive film.