Effects of water vapor anneal on MIS devices made of nitrided gate dielectrics

Silicon nitride and oxynitride films are known to possess a number of attractive properties over thermal SiO/sub 2/ as gate dielectric for Field-Effect Transistors (FETs), including better resistance to impurity diffusion and higher dielectric constant. However, their poor interface properties have prevented their use as a mainstream gate dielectric. Even in the case of nitrodized oxides where the nitrogen content is minute, the reduced peak transconductance for n-channel transistors is still a major concern for many applications, despite their much improved reliability. This paper shows that a modest annealing treatment in a steam furnace yields dramatic improvement of FET´s transconductance as well as its current driveability for devices containing nitrided gate while preserving their excellent reliability. Only results on silicon nitride based MNS devices are included.