Semiconductor device, method for manufacturing semiconductor device, module, and electronic device

Abstract

A semiconductor device with stable electrical characteristics is provided. Alternatively, a semiconductor device having normally-off electrical characteristics is provided. A semiconductor device includes a gate electrode, a gate insulator, and an oxide semiconductor, the oxide semiconductor contains fluorine in a channel formation region, and a fluorine concentration in the channel formation region is higher than or equal to 1×10 20 atoms/cm 3 and lower than or equal to 1×10 22 atoms/cm 3 . Note that fluorine is added by an ion implantation method.

What is claimed is: 
     
         1 . A semiconductor device comprising:
 an oxide semiconductor film including a channel formation region; and   a gate electrode adjacent to the channel formation region with a gate insulating layer therebetween,   wherein the oxide semiconductor film contains fluorine in the channel formation region, and   wherein a fluorine concentration in the channel formation region is higher than or equal to 1×10 20  atoms/cm 3  and lower than or equal to 1×10 22  atoms/cm 3 .   
     
     
         2 . The semiconductor device according to  claim 1 ,
 wherein the gate electrode is located above the oxide semiconductor film.   
     
     
         3 . The semiconductor device according to  claim 1 ,
 wherein in the oxide semiconductor film, a fluorine concentration in a region other than the channel formation region is lower than the fluorine concentration in the channel formation region.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein the oxide semiconductor film contains at least one selected from indium, zinc, and an element M (an element M is aluminum, gallium, yttrium, or tin).   
     
     
         5 . A module comprising:
 a printed board; and   the semiconductor device according to  claim 1  on the printed board.   
     
     
         6 . An electronic device comprising:
 the semiconductor device according to  claim 1 ; and   a speaker, an operation key, or a battery which is electrically connected to the semiconductor device.   
     
     
         7 . A semiconductor device comprising:
 a first oxide semiconductor film;   a second oxide semiconductor film including a channel formation region over the first oxide semiconductor film;   a third oxide semiconductor film over the second oxide semiconductor film; and   a gate electrode adjacent to the channel formation region with a gate insulating layer therebetween,   wherein the second oxide semiconductor film contains fluorine in the channel formation region, and   wherein a fluorine concentration in the channel formation region is higher than or equal to 1×10 20  atoms/cm 3  and lower than or equal to 1×10 22  atoms/cm 3 .   
     
     
         8 . The semiconductor device according to  claim 7 ,
 wherein the gate electrode is located above the third oxide semiconductor film.   
     
     
         9 . The semiconductor device according to  claim 7 ,
 wherein in the second oxide semiconductor film, a fluorine concentration in a region other than the channel formation region is lower than the fluorine concentration in the channel formation region.   
     
     
         10 . The semiconductor device according to  claim 7 ,
 wherein the first oxide semiconductor film and the third oxide semiconductor film contain fluorine.   
     
     
         11 . The semiconductor device according to  claim 7 ,
 wherein the second oxide semiconductor film contains at least one selected from indium, zinc, and an element M (an element M is aluminum, gallium, yttrium, or tin).   
     
     
         12 . A module comprising:
 a printed board; and   the semiconductor device according to  claim 7  on the printed board.   
     
     
         13 . An electronic device comprising:
 the semiconductor device according to  claim 7 ; and   a speaker, an operation key, or a battery which is electrically connected to the semiconductor device.   
     
     
         14 . A method for manufacturing a semiconductor device, comprising the steps of:
 forming an oxide semiconductor film over a substrate;   forming a source electrode and a drain electrode in contact with the oxide semiconductor film;   adding fluorine to the oxide semiconductor film;   forming an insulating film over the oxide semiconductor film, the source electrode, and the drain electrode; and   forming a gate electrode over the insulating film.   
     
     
         15 . The method for manufacturing a semiconductor device, according to  claim 14 ,
 wherein the source electrode and the drain electrode are over the oxide semiconductor film.   
     
     
         16 . The method for manufacturing a semiconductor device, according to  claim 14 ,
 wherein the fluorine is added to the oxide semiconductor film through the insulating film.   
     
     
         17 . The method for manufacturing a semiconductor device, according to  claim 14 ,
 wherein the fluorine is added by an ion implantation method.   
     
     
         18 . The method for manufacturing a semiconductor device, according to claim  14 ,
 wherein the oxide semiconductor film contains at least one selected from indium, zinc, and an element M (an element M is aluminum, gallium, yttrium, or tin).