| abstract |
PROBLEM TO BE SOLVED: To provide a method of manufacturing a semiconductor device having a stable threshold voltage, excellent characteristics and reliability, and an ONO laminated film as a gate insulating film. After an ONO laminated film 5 made of silicon oxide films 2 and 4 and a silicon nitride film 3 is formed on a semiconductor substrate 1, one of the following charge accumulation suppressing processes is performed on the silicon nitride film 3. After the charge accumulation process, charges are injected into the ONO multilayer film 5 by plasma dry etching or plasma chemical vapor deposition. In the charge accumulation treatment, the silicon nitride film 3 is oxidized by heating to a high temperature in a mixed gas of unreacted hydrogen and oxygen to react with hydrogen and oxygen, or in a high temperature hydrogen atmosphere that is oxidized in an oxidizing atmosphere containing chlorine. And the like that oxidize a silicon nitride film. [Selection] Figure 1 |