IMPROVEMENT OF THE SIO2 SI INTERFACE OF METAL-OXIDE-SEMICONDUCTOR DEVICES USING GATE DIELECTRICS FORMED BY NF3-AIDED OXIDATION AND N2O POSTANNEALING/

With the increasing requirement for ultrathin gate dielectrics in adva nced metal-oxide-semiconductor structures, a low thermal budget proces s to grow thin dielectric film is vital, while at the same time mainta ining the good interface quality and thin film reliability. In this ar ticle, thermal nitridation of fluorinated oxide in N2O ambient was inv estigated. While fluorinated oxides provide a lower thin film stress a nd better interface than conventional oxides, an excess amount of fluo rine in the starting oxide has an adverse effect on the high field sta bility. For N2O-nitrided oxide, high temperature and prolonged nitrida tion time reduce the interface state generation DELTAD(it) resulting f rom avalanche electron injection at the expense of increasing the flat band voltage shift DELTAV(fb). The electrical properties are strongly process dependent. The best operating window of N2O nitridation of flu orinated oxide (F-ox), grown at 900-degrees-C with a 100 ppm NF3 addit ive, lies between 30 and 120 min at 950-degrees-C. With careful contro l of fluorinated oxide growth parameters and N2O annealing, we have de monstrated an excellent way to fabricate dielectric thin films for fut ure applications.