Advantages of thermal nitride and nitroxide gate films in VLSI process

Thin gate SiO2 films thinner than 200 A often deteriorate throughout developmental VLSI processes, including refractory metal or silicide gates and ion- or plasma-assisted processes. Thermal nitridation of such SiO2 films improves the MOS characteristics by producing surface protective layers against impurity penetration and by producing good interfacial characteristics. This fact indicates that a thermally grown silicon nitride film on a silicon substrate is the most promising candidate for a very-thin gate insulator. Experimental data show significant benefits from the nitride film for future VLSI devices.