Ultrathin SiOxNy by rapid thermal heating of silicon in N-2 at T=760-1050 degrees C

In this letter, we report on the reaction between Si and N-2 in the temperature range of 760-1050 degrees C, in a rapid thermal processing chamber, Gas phase impurities such as H2O, O-2, and H-2, which can outgas from the cold walls of the chamber, mediate the Si/N-2 reaction, resulting in the formation of SiOxNy. The oxynitridation can be explained by equilibrium chemical thermodynamics, in contrast to the case of oxynitridation using N2O or NO, where the nitrogen is incorporated under nonequilibrium conditions. Using nuclear reaction analysis, we have measured nitrogen contents as high as 2.5 x 10(15) N/cm(2) (the equivalent of more than 3 monolayers) in these new dielectrics. They can be reoxidized to form ultrathin 42 to 3 nm) dielectrics. (C) 1997 American Institute of Physics.