Semiconductor device and method for manufacturing the same

Abstract

A semiconductor device in which fluctuation in electric characteristics due to miniaturization is less likely to be caused is provided. The semiconductor device includes an oxide semiconductor film including a first region, a pair of second regions in contact with side surfaces of the first region, and a pair of third regions in contact with side surfaces of the pair of second regions; a gate insulating film provided over the oxide semiconductor film; and a first electrode that is over the gate insulating film and overlaps with the first region. The first region is a CAAC oxide semiconductor region. The pair of second regions and the pair of third regions are each an amorphous oxide semiconductor region containing a dopant. The dopant concentration of the pair of third regions is higher than the dopant concentration of the pair of second regions.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 an insulating film;   an oxide semiconductor film on the insulating film, the oxide semiconductor film comprising:
 a first region; 
 a pair of second regions, the first region located between the pair of second regions; and 
 a pair of third regions, the first region and the pair of second regions located between the pair of third regions; 
   a gate insulating film over the oxide semiconductor film; and   a first electrode over the gate insulating film and overlapping with the first region,   wherein each of a crystallinity of the pair of second regions and a crystallinity of the pair of third regions is lower than a crystallinity of the first region.   
     
     
         3 . The semiconductor device according to  claim 2 , further comprising:
 a first sidewall insulating film and a second sidewall insulating film located on side surfaces of the first electrode,   wherein the first sidewall insulating film overlaps with one of the pair of second regions, and the second sidewall insulating film overlaps with the other of the pair of second regions.   
     
     
         4 . The semiconductor device according to  claim 2 ,
 wherein the first region is a c-axis aligned crystal oxide semiconductor region.   
     
     
         5 . The semiconductor device according to  claim 2 , further comprising:
 a second electrode electrically connected to one of the pair of third regions; and   a third electrode electrically connected to the other of the pair of third regions.   
     
     
         6 . The semiconductor device according to  claim 5 ,
 wherein the second electrode is in contact with a top surface of the one of the pair of third regions, and   wherein the third electrode is in contact with a top surface of the other of the pair of third regions.   
     
     
         7 . The semiconductor device according to  claim 5 ,
 wherein the second electrode is in contact with a bottom surface of the one of the pair of third regions, and   wherein the third electrode is in contact with a bottom surface of the other of the pair of third regions.   
     
     
         8 . The semiconductor device according to  claim 2 ,
 wherein the gate insulating film overlaps with the first region, the pair of second regions, and the pair of third regions.   
     
     
         9 . The semiconductor device according to  claim 2 ,
 wherein the gate insulating film is an oxide insulating film.   
     
     
         10 . The semiconductor device according to  claim 2 ,
 wherein the pair of second regions and the pair of third regions comprise one or more elements selected from nitrogen, phosphorus, and arsenic as the dopant, and   wherein the dopant concentration of the pair of second regions and the dopant concentration of the pair of third regions are higher than or equal to 5×10 18  atoms/cm 3  and lower than or equal to 1×10 22  atoms/cm 3 .   
     
     
         11 . The semiconductor device according to  claim 2 ,
 wherein the pair of second regions and the pair of third regions comprise one or more elements selected from nitrogen, phosphorus, and arsenic as the dopant,   wherein the dopant concentration of the pair of second regions is higher than or equal to 5×10 18  atoms/cm 3  and lower than 5×10 19  atoms/cm 3 , and   wherein the dopant concentration of the pair of third regions is higher than or equal to 5×10 19  atoms/cm 3  and lower than or equal to 1×10 22  atoms/cm 3 .   
     
     
         12 . The semiconductor device according to  claim 2 ,
 wherein the oxide semiconductor film comprises two or more elements selected from In, Ga, Sn, and Zn.   
     
     
         13 . A semiconductor device comprising:
 a base insulating film;   an oxide semiconductor film on an insulating surface of the base insulating film, the oxide semiconductor film including a channel formation region and a pair of impurity regions with the channel formation region therebetween, wherein the oxide semiconductor film comprises indium and zinc;   a gate insulating film over the oxide semiconductor film;   a gate electrode over the channel formation region of the oxide semiconductor film with the gate insulating film interposed therebetween; and   first insulating films on side surfaces of the gate electrode, the first insulating films comprising silicon nitride,   wherein each of the pair of impurity regions comprises a first region and a second region, the first region being located between the channel formation region and the second region,   wherein the first regions of the pair of impurity regions are overlapped with the first insulating films while the second regions of the pair of impurity regions are not overlapped with the first insulating films, and   wherein the pair of impurity regions of the oxide semiconductor film contains nitrogen at a higher concentration than the channel formation region.   
     
     
         14 . The semiconductor device according to  claim 13 ,
 wherein the channel formation region is a c-axis aligned crystal oxide semiconductor region.   
     
     
         15 . The semiconductor device according to  claim 13 ,
 wherein the second region contains nitrogen at a higher concentration than the first region.   
     
     
         16 . The semiconductor device according to  claim 13 , further comprising a second insulating film over the gate electrode,
 wherein the second insulating film is in contact with the first insulating films and the second regions of the pair of impurity regions, and   wherein the second insulating film comprises a material selected from the group consisting of silicon oxide, silicon oxynitride, silicon nitride oxide, and silicon nitride.   
     
     
         17 . The semiconductor device according to  claim 13 , further comprising a transistor having a channel formation region comprising single crystalline silicon, wherein the transistor is operationally connected to the oxide semiconductor film. 
     
     
         18 . The semiconductor device according to  claim 13 ,
 wherein the oxide semiconductor film comprises In, Ga, and Zn.   
     
     
         19 . The semiconductor device according to  claim 13 ,
 wherein a crystallinity of the pair of impurity regions is lower than a crystallinity of the channel formation region.   wherein a crystallinity of the pair of impurity regions is lower than a crystallinity of the channel formation region.