Semiconductor device and method for manufacturing the same
Electrical characteristics of a semiconductor device including the oxide semiconductor are improved. Furthermore, a highly reliable transistor with small variation in electrical characteristics is manufactured. An oxynitride insulating film functioning as a base insulating film and a transistor in contact with the oxynitride insulating film are provided. The transistor includes an oxide semiconductor film in contact with the oxynitride insulating film functioning as a base insulating film. The total amount of gas having a mass-to-charge ratio of 30 released from the oxynitride insulating film by heat treatment and double of the amount of a gas having a mass-to-charge ratio of 32 released from the oxynitride insulating film by heat treatment is greater than or equal to 5×10 15 /cm 2 and less than or equal to 5×10 16 /cm 2 , or greater than or equal to 5×10 15 /cm 2 and less than or equal to 3×10 16 /cm 2 .
1. A method for manufacturing a semiconductor device comprising the steps of:
forming an oxynitride insulating film;
forming an oxide semiconductor film over and in contact with the oxynitride insulating film;
performing a heat treatment after forming the oxide semiconductor film;
forming a pair of electrodes in contact with the oxide semiconductor film;
forming a gate insulating film in contact with the oxide semiconductor film; and
forming a gate electrode overlapping the oxide semiconductor film,
wherein a total of an amount of a gas having a mass-to-charge ratio of 30 released from the oxynitride insulating film by the heat treatment and double of an amount of a gas having a mass-to-charge ratio of 32 released from the oxynitride insulating film by the heat treatment is greater than or equal to 5×10 15 /cm 2 and less than or equal to 5×10 16 /cm 2 , and
wherein the gas having a mass-to-charge ratio of 30 is nitrogen monoxide and the gas having a mass-to-charge ratio of 32 is oxygen.
2. The method for manufacturing a semiconductor device according to claim 1 , wherein the oxynitride insulating film contains oxygen at a higher proportion than oxygen in a stoichiometric composition.
3. The method for manufacturing a semiconductor device according to claim 1 , wherein the oxynitride insulating film contains oxygen at a higher proportion than nitrogen.
4. The method for manufacturing a semiconductor device according to claim 1 , wherein a thickness of oxynitride insulating film is greater than or equal to 100 nm and less than or equal to 3000 nm.
5. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the total of an amount of the gas having the mass-to-charge ratio of 30 released from the oxynitride insulating film by the heat treatment and double of the amount of the gas having the mass-to-charge ratio of 32 released from the oxynitride insulating film by the heat treatment is measured by thermal desorption spectroscopy.
6. The method for manufacturing a semiconductor device according to claim 1 ,
wherein, in the step of performing a heat treatment, supplying oxygen to the oxide semiconductor film is performed.
7. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the oxynitride insulating film is formed using dinitrogen monoxide or nitrogen dioxide.
8. A method for manufacturing a semiconductor device comprising the steps of:
forming an oxynitride insulating film;
forming an oxide semiconductor film over and in contact with the oxynitride insulating film;
performing a heat treatment after forming the oxide semiconductor film;
forming a pair of electrodes in contact with the oxide semiconductor film;
forming a gate insulating film in contact with the oxide semiconductor film; and
forming a gate electrode overlapping the oxide semiconductor film,
wherein a total of an amount of a gas having a mass-to-charge ratio of 30 released from the oxynitride insulating film by the heat treatment and double of an amount of a gas having a mass-to-charge ratio of 32 released from the oxynitride insulating film by the heat treatment is greater than or equal to 1×10 20 /cm 3 and less than or equal to 1×10 21 /cm 3 , and
wherein the gas having a mass-to-charge ratio of 30 is nitrogen monoxide and the gas having a mass-to-charge ratio of 32 is oxygen.
9. The method for manufacturing a semiconductor device according to claim 8 , wherein the oxynitride insulating film contains oxygen at a higher proportion than oxygen in a stoichiometric composition.
10. The method for manufacturing a semiconductor device according to claim 8 , wherein the oxynitride insulating film contains oxygen at a higher proportion than nitrogen.
11. The method for manufacturing a semiconductor device according to claim 8 , wherein a thickness of oxynitride insulating film is greater than or equal to 100 nm and less than or equal to 3000 nm.
12. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the total of an amount of the gas having the mass-to-charge ratio of 30 released from the oxynitride insulating film by the heat treatment and double of the amount of the gas having the mass-to-charge ratio of 32 released from the oxynitride insulating film by the heat treatment is measured by thermal desorption spectroscopy.
13. The method for manufacturing a semiconductor device according to claim 8 ,
wherein, in the step of performing a heat treatment, supplying oxygen to the oxide semiconductor film is performed.
14. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the oxynitride insulating film is formed using dinitrogen monoxide or nitrogen dioxide.