Abstract
We have proposed an approach to grow thin oxynitride gate dielectric (equivalent oxide thickness = 23.4 Å) with the capability for preventing boron penetration. In this method, oxynitride is formed by dry oxidation of ultrathin thermal nitride grown in low pressure. The secondary ion mass spectroscopy profile indicates that its nitrogen peak is located at the gate dielectric surface and possesses concentrations as high as 5.11 × 10 21 atom/cm 3 . Transmission electron spectroscopy analysis shows that this oxynitride has uniform thickness and a very smooth interface with the Si substrate. Surface roughness is also evaluated by atomic force spectroscopy and exhibits acceptable roughness for device operation. The capability to suppress boron penetration is further proven by the flatband voltage shift in C-V measurement. In addition, its practicality for device operation is also characterized by electrical performances for gate dielectric integrity and reliability. Most importantly, this process is not complicated and fully compatible with existent ultralarge scale integration technology.