Method for forming oxide semiconductor film, semiconductor device, and method for manufacturing semiconductor device

Abstract

The impurity concentration in the oxide semiconductor film is reduced, and a highly reliability can be obtained.

1 . A method for forming an oxide semiconductor film, comprising:
 supplying a gas containing one or more selected from the group consisting of a rare gas and oxygen into a deposition chamber in which partial pressures of a gas having a mass-to-charge ratio of 18, a gas having a mass-to-charge ratio of 28, and a gas having a mass-to-charge ratio of 44, which are measured with a quadrupole mass analyzer, are each 3×10 −5  Pa or less; and   forming an oxide semiconductor film in the deposition chamber by a sputtering method.   
     
     
         2 . A method for forming an oxide semiconductor film, comprising:
 supplying a gas containing one or more selected from the group consisting of a rare gas and oxygen into a deposition chamber in which leakage rates of a gas having a mass-to-charge ratio of 44, a gas having a mass-to-charge ratio of 18, and a gas having a mass-to-charge ratio of 28, which are measured with a quadrupole mass analyzer, are 3×10 −6  Pa·m 3 /s or less, 1×10 −7  Pa·m 3 /s or less, and 1×10 −5  Pa·m 3 /s, respectively; and   forming an oxide semiconductor film in the deposition chamber by a sputtering method.   
     
     
         3 . A semiconductor device comprising:
 a transistor comprising:
 an oxide semiconductor film; 
 a gate insulating film in contact with the oxide semiconductor film; and 
 a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween, 
   wherein a carbon concentration in the oxide semiconductor film, which is measured by secondary ion mass spectrometry, is lower than 5×10 19  atoms/cm 3 .   
     
     
         4 . The semiconductor device according to  claim 3 ,
 wherein a hydrogen concentration in the oxide semiconductor film, which is measured by secondary ion mass spectrometry, is lower than 5×10 19  atoms/cm 3 .   
     
     
         5 . The semiconductor device according to  claim 3 ,
 wherein a nitrogen concentration in the oxide semiconductor film, which is measured by secondary ion mass spectrometry, is lower than 5×10 19  atoms/cm 3 .   
     
     
         6 . A method for manufacturing a semiconductor device comprising:
 forming an oxide semiconductor film, a gate insulating film adjacent to the oxide semiconductor film, and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween,   wherein the oxide semiconductor film is formed by supplying a gas containing one or more selected from the group consisting of a rare gas and oxygen into a deposition chamber in which a partial pressure of a gas having a mass-to-charge ratio of 44, which is measured with a quadrupole mass analyzer, is 3×10 −5  Pa or less, and performing a sputtering method in which power is applied to a target in the deposition chamber.   
     
     
         7 . The method for manufacturing a semiconductor device, according to  claim 6 , wherein the gate electrode is formed over the oxide semiconductor film. 
     
     
         8 . The method for manufacturing a semiconductor device, according to  claim 6 , wherein the oxide semiconductor film is formed over the gate electrode. 
     
     
         9 . The method for manufacturing a semiconductor device, according to  claim 6 ,
 wherein a partial pressure of a gas having a mass-to-charge ratio of 18, which is measured with a quadrupole mass analyzer, is 3×10 −5  Pa or less in the deposition chamber.   
     
     
         10 . The method for manufacturing a semiconductor device, according to  claim 6 ,
 wherein a partial pressure of a gas having a mass-to-charge ratio of 28, which is measured with a quadrupole mass analyzer, is 3×10 −5  Pa or less in the deposition chamber.   
     
     
         11 . The method for manufacturing a semiconductor device according to  claim 6 ,
 wherein partial pressures of a gas having a mass-to-charge ratio of 18 and a gas having a mass-to-charge ratio of 28, which are measured with a quadrupole mass analyzer, are each 3×10 −5  Pa or less in the deposition chamber.   
     
     
         12 . A method for manufacturing a semiconductor device, comprising:
 forming a transistor including an oxide semiconductor film, a gate insulating film in contact with the oxide semiconductor film, and a gate electrode overlapping with the oxide semiconductor film with the gate insulating film interposed therebetween,   wherein the oxide semiconductor film is formed by supplying a gas containing one or more selected from the group consisting of a rare gas and oxygen into a deposition chamber in which a leakage rate of a gas having a mass-to-charge ratio of 44, which is measured with a quadrupole mass analyzer, is 3×10 −6  Pa·m 3 /s or less, and performing a sputtering method in the deposition chamber.   
     
     
         13 . The method for manufacturing a semiconductor device, according to  claim 12 ,
 wherein a leakage rate of a gas having a mass-to-charge ratio of 18, which is measured with a quadrupole mass analyzer, is 1×10 −7  Pa·m 3 /s or less in the deposition chamber.   
     
     
         14 . The method for manufacturing a semiconductor device, according to  claim 12 ,
 wherein a leakage rate of a gas having a mass-to-charge ratio of 28, which is measured with a quadrupole mass analyzer, is 1×10 −5  Pa·m 3 /s or less in the deposition chamber.