Method for manufacturing a semiconductor device

A method for manufacturing a semiconductor device, comprising:

• exposing a silicon layer to a first atmosphere to form a nitride layer on the silicon layer, the first atmosphere containing a nitriding gas nitriding the silicon layer and a first diluent gas not actually reacting with the silicon layer during production, the ratio of the sum of the partial pressure of the first diluent gas and the partial pressure of the nitriding gas to the partial pressure of the nitriding gas being 5 or higher, and the total pressure of the first atmosphere being 3 Torr or higher but 40 Torr or lower;
• exposing the silicon layer having the nitride layer to a second atmosphere containing radical N* gas or radical N2* gas to form a first nitride film between the silicon layer and the nitride layer, and to form a second nitride film on the nitride layer;
• and
• exposing the silicon layer having the first nitride film, the nitride layer, and the second nitride film to a third atmosphere, the third atmosphere containing an oxidizing gas and a second diluent gas not actually reacting with the silicon layer during production.

A method for manufacturing a semiconductor device, comprising:

• exposing a silicon layer to a first atmosphere to form a nitride layer on the silicon layer, the first atmosphere containing a nitriding gas nitriding the silicon layer and a first diluent gas not actually reacting with the silicon layer during production, the ratio of the sum of the partial pressure of the first diluent gas and the partial pressure of the nitriding gas to the partial pressure of the nitriding gas being 5 or higher, and the total pressure of the first atmosphere being 3 Torr or higher but 40 Torr or lower;
• exposing the silicon layer having the nitride layer to a second atmosphere containing a nitride gas to form a first nitride film between the silicon layer and the nitride layer, and to form a second nitride film on the nitride layer;
• and
• exposing the silicon layer having the first nitride film, the nitride layer, and the second nitride film to a third atmosphere, the third atmosphere containing an oxidizing gas and a second diluent gas not actually reacting with the silicon layer during production,
• wherein a nitriding speed of forming the first and second nitride films is faster than that of forming the nitride layer.