Semiconductor device

Abstract

A semiconductor device includes a gate electrode, a gate insulating film which includes oxidized material containing silicon and covers the gate electrode, an oxide semiconductor film provided to be in contact with the gate insulating film and overlap with at least the gate electrode, and a source electrode and a drain electrode electrically connected to the oxide semiconductor film. In the oxide semiconductor film, a first region which is provided to be in contact with the gate insulating film and have a thickness less than or equal to 5 nm has a silicon concentration lower than or equal to 1.0 at. %, and a region in the oxide semiconductor film other than the first region has lower silicon concentration than the first region. At least the first region includes a crystal portion.

1 . A semiconductor device comprising:
 an insulating film and a gate electrode over a substrate;   an oxide semiconductor film in contact with the insulating film; and   a source electrode and a drain electrode electrically connected to the oxide semiconductor film,   wherein the insulating film includes silicon and oxygen,   wherein the oxide semiconductor film has a first region and a second region,   wherein the first region is located between the second region and the insulating film,   wherein a concentration of silicon in the second region is lower than a concentration of silicon in the first region,   wherein, in the first region, a concentration of carbon is lower than or equal to 1.0×10 20  atoms/cm 3 , and   wherein the oxide semiconductor film includes a crystal portion.   
     
     
         2 . A semiconductor device comprising:
 an insulating film and a gate electrode over a substrate;   an oxide semiconductor film in contact with the insulating film; and   a source electrode and a drain electrode electrically connected to the oxide semiconductor film,   wherein the insulating film includes silicon and oxygen,   wherein the oxide semiconductor film has a first region and a second region,   wherein the first region is in contact with the insulating film and has a thickness less than or equal to 5 nm,   wherein the first region is located between the second region and the insulating film,   wherein a concentration of silicon in the second region is lower than a concentration of silicon in the first region,   wherein, in the first region, a concentration of carbon is lower than or equal to 1.0×10 20  atoms/cm 3 , and   wherein the oxide semiconductor film includes a crystal portion.   
     
     
         3 . A semiconductor device comprising:
 an insulating film and a gate electrode over a substrate;   an oxide semiconductor film in contact with the insulating film; and   a source electrode and a drain electrode electrically connected to the oxide semiconductor film,   wherein the insulating film includes silicon and oxygen,   wherein the oxide semiconductor film has a first region and a second region,   wherein the first region is in contact with the insulating film and has a thickness less than or equal to 5 nm,   wherein the first region is located between the second region and the insulating film,   wherein a concentration of silicon in the second region is lower than a concentration of silicon in the first region,   wherein, in the first region, a concentration of carbon is lower than or equal to 1.0×10 19  atoms/cm 3 , and   wherein the oxide semiconductor film includes a crystal portion.   
     
     
         4 . The semiconductor device according to  claim 1 ,
 wherein, in the crystal portion, a c-axis is aligned in a direction perpendicular to a surface where the oxide semiconductor film is formed, and   wherein the perpendicular includes a range of 85° to 95°.   
     
     
         5 . The semiconductor device according to  claim 2 ,
 wherein, in the crystal portion, a c-axis is aligned in a direction perpendicular to a surface where the oxide semiconductor film is formed, and   wherein the perpendicular includes a range of 85° to 95°.   
     
     
         6 . The semiconductor device according to  claim 3 ,
 wherein, in the crystal portion, a c-axis is aligned in a direction perpendicular to a surface where the oxide semiconductor film is formed, and   wherein the perpendicular includes a range of 85° to 95°.   
     
     
         7 . The semiconductor device according to  claim 1 ,
 wherein the oxide semiconductor film is formed by an atomic layer deposition method.   
     
     
         8 . The semiconductor device according to  claim 2 ,
 wherein the oxide semiconductor film is formed by an atomic layer deposition method.   
     
     
         9 . The semiconductor device according to  claim 3 ,
 wherein the oxide semiconductor film is formed by an atomic layer deposition method.   
     
     
         10 . The semiconductor device according to  claim 1 ,
 wherein the oxide semiconductor film is an In—Zn-based oxide, a Sn—Zn-based oxide, an Al—Zn-based oxide, a Zn—Mg-based oxide, a Sn—Mg-based oxide, an In—Mg-based oxide, an In—Ga-based oxide, an In—Ga—Zn-based oxide, an In—Al—Zn-based oxide, an In—Sn—Zn-based oxide, a Sn—Ga—Zn-based oxide, an Al—Ga—Zn-based oxide, a Sn—Al—Zn-based oxide, an In—Hf—Zn-based oxide, an In—Zr—Zn-based oxide, an In—Ti—Zn-based oxide, an In—Sc—Zn-based oxide, an In—Y—Zn-based oxide, an In—La—Zn-based oxide, an In—Ce—Zn-based oxide, an In—Pr—Zn-based oxide, an In—Nd—Zn-based oxide, an In—Sm—Zn-based oxide, an In—Eu—Zn-based oxide, an In—Gd—Zn-based oxide, an In—Tb—Zn-based oxide, an In—Dy—Zn-based oxide, an In—Ho—Zn-based oxide, an In—Er—Zn-based oxide, an In—Tm—Zn-based oxide, an In—Yb—Zn-based oxide, an In—Lu—Zn-based oxide, an In—Sn—Ga—Zn-based oxide, an In—Hf—Ga—Zn-based oxide, an In—Al—Ga—Zn-based oxide, an In—Sn—Al—Zn-based oxide, an In—Sn—Hf—Zn-based oxide, or an In—Hf—Al—Zn-based oxide.   
     
     
         11 . The semiconductor device according to  claim 2 ,
 wherein the oxide semiconductor film is an In—Zn-based oxide, a Sn—Zn-based oxide, an Al—Zn-based oxide, a Zn—Mg-based oxide, a Sn—Mg-based oxide, an In—Mg-based oxide, an In—Ga-based oxide, an In—Ga—Zn-based oxide, an In—Al—Zn-based oxide, an In—Sn—Zn-based oxide, a Sn—Ga—Zn-based oxide, an Al—Ga—Zn-based oxide, a Sn—Al—Zn-based oxide, an In—Hf—Zn-based oxide, an In—Zr—Zn-based oxide, an In—Ti—Zn-based oxide, an In—Sc—Zn-based oxide, an In—Y—Zn-based oxide, an In—La—Zn-based oxide, an In—Ce—Zn-based oxide, an In—Pr—Zn-based oxide, an In—Nd—Zn-based oxide, an In—Sm—Zn-based oxide, an In—Eu—Zn-based oxide, an In—Gd—Zn-based oxide, an In—Tb—Zn-based oxide, an In—Dy—Zn-based oxide, an In—Ho—Zn-based oxide, an In—Er—Zn-based oxide, an In—Tm—Zn-based oxide, an In—Yb—Zn-based oxide, an In—Lu—Zn-based oxide, an In—Sn—Ga—Zn-based oxide, an In—Hf—Ga—Zn-based oxide, an In—Al—Ga—Zn-based oxide, an In—Sn—Al—Zn-based oxide, an In—Sn—Hf—Zn-based oxide, or an In—Hf—Al—Zn-based oxide.   
     
     
         12 . The semiconductor device according to  claim 3 ,
 wherein the oxide semiconductor film is an In—Zn-based oxide, a Sn—Zn-based oxide, an Al—Zn-based oxide, a Zn—Mg-based oxide, a Sn—Mg-based oxide, an In—Mg-based oxide, an In—Ga-based oxide, an In—Ga—Zn-based oxide, an In—Al—Zn-based oxide, an In—Sn—Zn-based oxide, a Sn—Ga—Zn-based oxide, an Al—Ga—Zn-based oxide, a Sn—Al—Zn-based oxide, an In—Hf—Zn-based oxide, an In—Zr—Zn-based oxide, an In—Ti—Zn-based oxide, an In—Sc—Zn-based oxide, an In—Y—Zn-based oxide, an In—La—Zn-based oxide, an In—Ce—Zn-based oxide, an In—Pr—Zn-based oxide, an In—Nd—Zn-based oxide, an In—Sm—Zn-based oxide, an In—Eu—Zn-based oxide, an In—Gd—Zn-based oxide, an In—Tb—Zn-based oxide, an In—Dy—Zn-based oxide, an In—Ho—Zn-based oxide, an In—Er—Zn-based oxide, an In—Tm—Zn-based oxide, an In—Yb—Zn-based oxide, an In—Lu—Zn-based oxide, an In—Sn—Ga—Zn-based oxide, an In—Hf—Ga—Zn-based oxide, an In—Al—Ga—Zn-based oxide, an In—Sn—Al—Zn-based oxide, an In—Sn—Hf—Zn-based oxide, or an In—Hf—Al—Zn-based oxide.   
     
     
         13 . The semiconductor device according to  claim 1 ,
 wherein a carrier concentration of the oxide semiconductor film is lower than 1×10 14 /cm 3 .   
     
     
         14 . The semiconductor device according to  claim 2 ,
 wherein a carrier concentration of the oxide semiconductor film is lower than 1×10 14 /cm 3 .   
     
     
         15 . The semiconductor device according to  claim 3 ,
 wherein a carrier concentration of the oxide semiconductor film is lower than 1×10 14 /cm 3 .