Influence of the oxidation in the metal silicide/Si3N4 interfaces on the etching profile

Metal silicide has been proposed, studied and used as gate, word, and bit-line materials since it has considerably low resistance compared with the conventional materials like polysilicon. However, there are several serious problems encountered because the silicide is oxidized and forms a native oxide (SiO2) layer at the interface between metal silicide and Si3N4 film. In this study, we have introduced 10 slm N2 gas from top to bottom of the modified quartz tube in order to decrease the oxygen concentration in the tube by using the long injector system. The result shows that there is no oxidation occurred when the flow rate of N2 gas is sufficiently high.