Heat treatment method for semiconductor substrate.

摘要

In the heat treatment method of a semiconductor substrate, a semiconductor substrate is placed in a furnace and heat treated in a reducing or inert atmosphere at temperature higher than 1100 DEG C for a predetermined time; the reducing or inert atmosphere is replaced with nitrogen gas, after the atmosphere has been lowered to or when being lowered to a predetermined temperature; and thereafter the heat treated semiconductor substrate is taken out from the furnace. In particular, the predetermined temperature lies between 600 DEG C and 850 DEG C. In the above heat treatment method, although the substrate is heat treated in the reducing or inert atmosphere at 1100 DEG C or higher, since the atmosphere is replaced with the nitrogen gas at enough low temperature that a nitride film which increases the surface roughness of the substrate is not formed on the substrate surface, thus eliminating gate oxide deterioration caused by the nitridation itself.