HIGH-PERFORMANCE NITRIDED OXIDES FABRICATED BY VERY-LOW-PRESSURE NITRIDATION TECHNIQUE

A never and simple method is proposed to produce high-performance nitr ided oxides. Thin oxides nitrided only in NH3 at 900 degrees C for 1 h at 0.1 Torr have excellent interface stability, few electron traps, a nd excellent reliability. Although the nitrogen concentration [N] at t he dielectric/Si substrate interface is kept at a low value, the hydro gen concentration [H] has been shown to be comparable to that of pure oxide at the beginning of the nitridation. Consequently, a high ratio of [N]/[K], which reflects the stable interface, can be attained at th e initial stage of the very-low-pressure nitridation (VLPN). This is v ery different from the case of conventional low-pressure nitridation. The retarded formations of the interfacial Si3N4 and the surface nitro gen-rich oxynitrides are conjectured to be the main cause of reduction in the hydrogen content in the dielectrics during VLPN. Due to the si mplicity and wide process window, VLPN is promising for the future ult ra-large-scale-integration (ULSI) technology.